<?xml version="1.0" encoding="us-ascii"?>
<!--Generated by EDGARfilings PROfile 8.0.0.0 Broadridge-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:t1="http://xbrl.org/2005/xbrldt">
  <link:roleRef roleURI="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationCondensedStatementOfCashFlowsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#ParentCompanyOnlyCondensedFinancialInformationCondensedStatementOfCashFlowsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationCondensedStatementOfOperationsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#ParentCompanyOnlyCondensedFinancialInformationCondensedStatementOfOperationsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationCondensedBalanceSheetDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#ParentCompanyOnlyCondensedFinancialInformationCondensedBalanceSheetDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RestrictedNetAssetsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#RestrictedNetAssetsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/CommitmentsAndContingenciesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#CommitmentsAndContingenciesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SegmentInformationDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SegmentInformationDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/IncomeTaxesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#IncomeTaxesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/StockbasedCompensationShareOptionActivitiesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#StockbasedCompensationShareOptionActivitiesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/StockbasedCompensationAssumptionsUsedToDetermineFairValueOfShareOptionsGrantedDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#StockbasedCompensationAssumptionsUsedToDetermineFairValueOfShareOptionsGrantedDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/StockbasedCompensationStockbasedCompensationExpenseDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#StockbasedCompensationStockbasedCompensationExpenseDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RedeemableNoncontrollingInterestsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#RedeemableNoncontrollingInterestsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/CommonStockDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#CommonStockDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RelatedPartyBalancesAndTransactionsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#RelatedPartyBalancesAndTransactionsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/TradingSecuritiesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#TradingSecuritiesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/FinancialLiabilityCarriedAtFairValueDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#FinancialLiabilityCarriedAtFairValueDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LongtermInvestmentDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#LongtermInvestmentDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherLongtermLiabilitiesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherLongtermLiabilitiesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LongtermBorrowingsDetailsCalc2" xlink:type="simple" xlink:href="acmr-20211231.xsd#LongtermBorrowingsDetailsCalc2" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LongtermBorrowingsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#LongtermBorrowingsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LeasesDetailsCalc01" xlink:type="simple" xlink:href="acmr-20211231.xsd#LeasesDetailsCalc01" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LeasesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#LeasesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherPayableAndAccruedExpensesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherPayableAndAccruedExpensesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ShorttermBorrowingsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#ShorttermBorrowingsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherLongtermAssetsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherLongtermAssetsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LandUseRightNetDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#LandUseRightNetDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/PropertyPlantAndEquipmentNetDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#PropertyPlantAndEquipmentNetDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/InventoriesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#InventoriesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/AccountsReceivableDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#AccountsReceivableDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RevenueFromContractsWithCustomersDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#RevenueFromContractsWithCustomersDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesOperatingAndFinancialRisksDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesOperatingAndFinancialRisksDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesStatutoryReservesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesStatutoryReservesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesComprehensiveIncomeAttributableToCompanyDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesComprehensiveIncomeAttributableToCompanyDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesBasicAndDilutedNetIncomePerCommonShareDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesBasicAndDilutedNetIncomePerCommonShareDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesGovernmentSubsidiesDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesGovernmentSubsidiesDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesWarrantyDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesWarrantyDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesShippingAndHandlingCostsDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesShippingAndHandlingCostsDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesIntangibleAssetsNetDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesIntangibleAssetsNetDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesPropertyPlantAndEquipmentNetDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesPropertyPlantAndEquipmentNetDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesInventoryDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesInventoryDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesLandUseRightsNetDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesLandUseRightsNetDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesAccountsReceivableDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesAccountsReceivableDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesRestrictedCashDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesRestrictedCashDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/DescriptionOfBusinessDetails" xlink:type="simple" xlink:href="acmr-20211231.xsd#DescriptionOfBusinessDetails" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#ParentCompanyOnlyCondensedFinancialInformationTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/IncomeTaxesTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#IncomeTaxesTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/StockbasedCompensationTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#StockbasedCompensationTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RedeemableNoncontrollingInterestsTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#RedeemableNoncontrollingInterestsTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RelatedPartyBalancesAndTransactionsTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#RelatedPartyBalancesAndTransactionsTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/TradingSecuritiesTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#TradingSecuritiesTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/FinancialLiabilityCarriedAtFairValueTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#FinancialLiabilityCarriedAtFairValueTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LongtermInvestmentTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#LongtermInvestmentTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherLongtermLiabilitiesTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherLongtermLiabilitiesTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LongtermBorrowingsTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#LongtermBorrowingsTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LeasesTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#LeasesTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherPayableAndAccruedExpensesTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherPayableAndAccruedExpensesTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ShorttermBorrowingsTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#ShorttermBorrowingsTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherLongtermAssetsTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherLongtermAssetsTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LandUseRightNetTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#LandUseRightNetTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/PropertyPlantAndEquipmentNetTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#PropertyPlantAndEquipmentNetTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/InventoriesTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#InventoriesTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/AccountsReceivableTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#AccountsReceivableTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RevenueFromContractsWithCustomersTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#RevenueFromContractsWithCustomersTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/DescriptionOfBusinessTables" xlink:type="simple" xlink:href="acmr-20211231.xsd#DescriptionOfBusinessTables" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPoliciesPolicies" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformation" xlink:type="simple" xlink:href="acmr-20211231.xsd#ParentCompanyOnlyCondensedFinancialInformation" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RestrictedNetAssets" xlink:type="simple" xlink:href="acmr-20211231.xsd#RestrictedNetAssets" />
  <link:roleRef roleURI="http://acmrcsh.com/role/CommitmentsAndContingencies" xlink:type="simple" xlink:href="acmr-20211231.xsd#CommitmentsAndContingencies" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SegmentInformation" xlink:type="simple" xlink:href="acmr-20211231.xsd#SegmentInformation" />
  <link:roleRef roleURI="http://acmrcsh.com/role/IncomeTaxes" xlink:type="simple" xlink:href="acmr-20211231.xsd#IncomeTaxes" />
  <link:roleRef roleURI="http://acmrcsh.com/role/StockbasedCompensation" xlink:type="simple" xlink:href="acmr-20211231.xsd#StockbasedCompensation" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RedeemableNoncontrollingInterests" xlink:type="simple" xlink:href="acmr-20211231.xsd#RedeemableNoncontrollingInterests" />
  <link:roleRef roleURI="http://acmrcsh.com/role/CommonStock" xlink:type="simple" xlink:href="acmr-20211231.xsd#CommonStock" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RelatedPartyBalancesAndTransactions" xlink:type="simple" xlink:href="acmr-20211231.xsd#RelatedPartyBalancesAndTransactions" />
  <link:roleRef roleURI="http://acmrcsh.com/role/TradingSecurities" xlink:type="simple" xlink:href="acmr-20211231.xsd#TradingSecurities" />
  <link:roleRef roleURI="http://acmrcsh.com/role/FinancialLiabilityCarriedAtFairValue" xlink:type="simple" xlink:href="acmr-20211231.xsd#FinancialLiabilityCarriedAtFairValue" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LongtermInvestment" xlink:type="simple" xlink:href="acmr-20211231.xsd#LongtermInvestment" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherLongtermLiabilities" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherLongtermLiabilities" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LongtermBorrowings" xlink:type="simple" xlink:href="acmr-20211231.xsd#LongtermBorrowings" />
  <link:roleRef roleURI="http://acmrcsh.com/role/Leases" xlink:type="simple" xlink:href="acmr-20211231.xsd#Leases" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherPayableAndAccruedExpenses" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherPayableAndAccruedExpenses" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ShorttermBorrowings" xlink:type="simple" xlink:href="acmr-20211231.xsd#ShorttermBorrowings" />
  <link:roleRef roleURI="http://acmrcsh.com/role/OtherLongtermAssets" xlink:type="simple" xlink:href="acmr-20211231.xsd#OtherLongtermAssets" />
  <link:roleRef roleURI="http://acmrcsh.com/role/LandUseRightNet" xlink:type="simple" xlink:href="acmr-20211231.xsd#LandUseRightNet" />
  <link:roleRef roleURI="http://acmrcsh.com/role/PropertyPlantAndEquipmentNet" xlink:type="simple" xlink:href="acmr-20211231.xsd#PropertyPlantAndEquipmentNet" />
  <link:roleRef roleURI="http://acmrcsh.com/role/Inventories" xlink:type="simple" xlink:href="acmr-20211231.xsd#Inventories" />
  <link:roleRef roleURI="http://acmrcsh.com/role/AccountsReceivable" xlink:type="simple" xlink:href="acmr-20211231.xsd#AccountsReceivable" />
  <link:roleRef roleURI="http://acmrcsh.com/role/RevenueFromContractsWithCustomers" xlink:type="simple" xlink:href="acmr-20211231.xsd#RevenueFromContractsWithCustomers" />
  <link:roleRef roleURI="http://acmrcsh.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="simple" xlink:href="acmr-20211231.xsd#SummaryOfSignificantAccountingPolicies" />
  <link:roleRef roleURI="http://acmrcsh.com/role/DescriptionOfBusiness" xlink:type="simple" xlink:href="acmr-20211231.xsd#DescriptionOfBusiness" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ConsolidatedStatementsOfCashFlowsParenthetical" xlink:type="simple" xlink:href="acmr-20211231.xsd#ConsolidatedStatementsOfCashFlowsParenthetical" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="simple" xlink:href="acmr-20211231.xsd#ConsolidatedStatementsOfCashFlows" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ConsolidatedStatementOfChangesInStockholdersEquity" xlink:type="simple" xlink:href="acmr-20211231.xsd#ConsolidatedStatementOfChangesInStockholdersEquity" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ConsolidatedStatementsOfOperationsAndComprehensiveIncome" xlink:type="simple" xlink:href="acmr-20211231.xsd#ConsolidatedStatementsOfOperationsAndComprehensiveIncome" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="acmr-20211231.xsd#ConsolidatedBalanceSheetsParenthetical" />
  <link:roleRef roleURI="http://acmrcsh.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="acmr-20211231.xsd#ConsolidatedBalanceSheets" />
  <link:roleRef roleURI="http://acmrcsh.com/role/DocumentAndEntityInformation" xlink:type="simple" xlink:href="acmr-20211231.xsd#DocumentAndEntityInformation" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/DocumentAndEntityInformation">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentInformationLineItems" xlink:label="DocumentInformationLineItems" xlink:title="DocumentInformationLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentType" xlink:label="DocumentType" xlink:title="DocumentType" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentType" xlink:title="definition: DocumentInformationLineItems to DocumentType" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AmendmentFlag" xlink:label="AmendmentFlag" xlink:title="AmendmentFlag" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="AmendmentFlag" xlink:title="definition: DocumentInformationLineItems to AmendmentFlag" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentAnnualReport" xlink:label="DocumentAnnualReport" xlink:title="DocumentAnnualReport" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentAnnualReport" xlink:title="definition: DocumentInformationLineItems to DocumentAnnualReport" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentPeriodEndDate" xlink:label="DocumentPeriodEndDate" xlink:title="DocumentPeriodEndDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentPeriodEndDate" xlink:title="definition: DocumentInformationLineItems to DocumentPeriodEndDate" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CurrentFiscalYearEndDate" xlink:label="CurrentFiscalYearEndDate" xlink:title="CurrentFiscalYearEndDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="CurrentFiscalYearEndDate" xlink:title="definition: DocumentInformationLineItems to CurrentFiscalYearEndDate" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalYearFocus" xlink:label="DocumentFiscalYearFocus" xlink:title="DocumentFiscalYearFocus" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentFiscalYearFocus" xlink:title="definition: DocumentInformationLineItems to DocumentFiscalYearFocus" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="DocumentFiscalPeriodFocus" xlink:title="DocumentFiscalPeriodFocus" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentFiscalPeriodFocus" xlink:title="definition: DocumentInformationLineItems to DocumentFiscalPeriodFocus" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentTransitionReport" xlink:label="DocumentTransitionReport" xlink:title="DocumentTransitionReport" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="DocumentTransitionReport" xlink:title="definition: DocumentInformationLineItems to DocumentTransitionReport" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFileNumber" xlink:label="EntityFileNumber" xlink:title="EntityFileNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityFileNumber" xlink:title="definition: DocumentInformationLineItems to EntityFileNumber" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityRegistrantName" xlink:label="EntityRegistrantName" xlink:title="EntityRegistrantName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityRegistrantName" xlink:title="definition: DocumentInformationLineItems to EntityRegistrantName" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCentralIndexKey" xlink:label="EntityCentralIndexKey" xlink:title="EntityCentralIndexKey" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityCentralIndexKey" xlink:title="definition: DocumentInformationLineItems to EntityCentralIndexKey" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityIncorporationStateCountryCode" xlink:label="EntityIncorporationStateCountryCode" xlink:title="EntityIncorporationStateCountryCode" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityIncorporationStateCountryCode" xlink:title="definition: DocumentInformationLineItems to EntityIncorporationStateCountryCode" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityTaxIdentificationNumber" xlink:label="EntityTaxIdentificationNumber" xlink:title="EntityTaxIdentificationNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityTaxIdentificationNumber" xlink:title="definition: DocumentInformationLineItems to EntityTaxIdentificationNumber" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressAddressLine1" xlink:label="EntityAddressAddressLine1" xlink:title="EntityAddressAddressLine1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityAddressAddressLine1" xlink:title="definition: DocumentInformationLineItems to EntityAddressAddressLine1" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressCityOrTown" xlink:label="EntityAddressCityOrTown" xlink:title="EntityAddressCityOrTown" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityAddressCityOrTown" xlink:title="definition: DocumentInformationLineItems to EntityAddressCityOrTown" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressStateOrProvince" xlink:label="EntityAddressStateOrProvince" xlink:title="EntityAddressStateOrProvince" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityAddressStateOrProvince" xlink:title="definition: DocumentInformationLineItems to EntityAddressStateOrProvince" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressPostalZipCode" xlink:label="EntityAddressPostalZipCode" xlink:title="EntityAddressPostalZipCode" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityAddressPostalZipCode" xlink:title="definition: DocumentInformationLineItems to EntityAddressPostalZipCode" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CityAreaCode" xlink:label="CityAreaCode" xlink:title="CityAreaCode" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="CityAreaCode" xlink:title="definition: DocumentInformationLineItems to CityAreaCode" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LocalPhoneNumber" xlink:label="LocalPhoneNumber" xlink:title="LocalPhoneNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="LocalPhoneNumber" xlink:title="definition: DocumentInformationLineItems to LocalPhoneNumber" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_Security12bTitle" xlink:label="Security12bTitle" xlink:title="Security12bTitle" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="Security12bTitle" xlink:title="definition: DocumentInformationLineItems to Security12bTitle" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_TradingSymbol" xlink:label="TradingSymbol" xlink:title="TradingSymbol" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="TradingSymbol" xlink:title="definition: DocumentInformationLineItems to TradingSymbol" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_SecurityExchangeName" xlink:label="SecurityExchangeName" xlink:title="SecurityExchangeName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="SecurityExchangeName" xlink:title="definition: DocumentInformationLineItems to SecurityExchangeName" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="EntityWellKnownSeasonedIssuer" xlink:title="EntityWellKnownSeasonedIssuer" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityWellKnownSeasonedIssuer" xlink:title="definition: DocumentInformationLineItems to EntityWellKnownSeasonedIssuer" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityVoluntaryFilers" xlink:label="EntityVoluntaryFilers" xlink:title="EntityVoluntaryFilers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityVoluntaryFilers" xlink:title="definition: DocumentInformationLineItems to EntityVoluntaryFilers" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCurrentReportingStatus" xlink:label="EntityCurrentReportingStatus" xlink:title="EntityCurrentReportingStatus" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityCurrentReportingStatus" xlink:title="definition: DocumentInformationLineItems to EntityCurrentReportingStatus" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityInteractiveDataCurrent" xlink:label="EntityInteractiveDataCurrent" xlink:title="EntityInteractiveDataCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityInteractiveDataCurrent" xlink:title="definition: DocumentInformationLineItems to EntityInteractiveDataCurrent" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFilerCategory" xlink:label="EntityFilerCategory" xlink:title="EntityFilerCategory" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityFilerCategory" xlink:title="definition: DocumentInformationLineItems to EntityFilerCategory" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntitySmallBusiness" xlink:label="EntitySmallBusiness" xlink:title="EntitySmallBusiness" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntitySmallBusiness" xlink:title="definition: DocumentInformationLineItems to EntitySmallBusiness" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityEmergingGrowthCompany" xlink:label="EntityEmergingGrowthCompany" xlink:title="EntityEmergingGrowthCompany" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityEmergingGrowthCompany" xlink:title="definition: DocumentInformationLineItems to EntityEmergingGrowthCompany" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_IcfrAuditorAttestationFlag" xlink:label="IcfrAuditorAttestationFlag" xlink:title="IcfrAuditorAttestationFlag" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="IcfrAuditorAttestationFlag" xlink:title="definition: DocumentInformationLineItems to IcfrAuditorAttestationFlag" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityShellCompany" xlink:label="EntityShellCompany" xlink:title="EntityShellCompany" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityShellCompany" xlink:title="definition: DocumentInformationLineItems to EntityShellCompany" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityPublicFloat" xlink:label="EntityPublicFloat" xlink:title="EntityPublicFloat" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityPublicFloat" xlink:title="definition: DocumentInformationLineItems to EntityPublicFloat" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="EntityCommonStockSharesOutstanding" xlink:title="EntityCommonStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="EntityCommonStockSharesOutstanding" xlink:title="definition: DocumentInformationLineItems to EntityCommonStockSharesOutstanding" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AuditorFirmId" xlink:label="AuditorFirmId" xlink:title="AuditorFirmId" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="AuditorFirmId" xlink:title="definition: DocumentInformationLineItems to AuditorFirmId" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AuditorName" xlink:label="AuditorName" xlink:title="AuditorName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="AuditorName" xlink:title="definition: DocumentInformationLineItems to AuditorName" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AuditorLocation" xlink:label="AuditorLocation" xlink:title="AuditorLocation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentInformationLineItems" xlink:to="AuditorLocation" xlink:title="definition: DocumentInformationLineItems to AuditorLocation" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentInformationTable" xlink:label="DocumentInformationTable" xlink:title="DocumentInformationTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DocumentInformationLineItems" xlink:to="DocumentInformationTable" xlink:title="definition: DocumentInformationLineItems to DocumentInformationTable" order="37.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DocumentInformationTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: DocumentInformationTable to StatementClassOfStockAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="CommonClassBMember" xlink:title="CommonClassBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassBMember" xlink:title="definition: ClassOfStockDomain to CommonClassBMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ConsolidatedBalanceSheets">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="AssetsAbstract" xlink:title="AssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AssetsAbstract" xlink:title="definition: StatementLineItems to AssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="LiabilitiesAndStockholdersEquityAbstract" xlink:title="LiabilitiesAndStockholdersEquityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LiabilitiesAndStockholdersEquityAbstract" xlink:title="definition: StatementLineItems to LiabilitiesAndStockholdersEquityAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="LiabilitiesCurrentAbstract" xlink:title="LiabilitiesCurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LiabilitiesCurrentAbstract" xlink:title="definition: StatementLineItems to LiabilitiesCurrentAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="LongTermDebtNoncurrent" xlink:title="LongTermDebtNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LongTermDebtNoncurrent" xlink:title="definition: StatementLineItems to LongTermDebtNoncurrent" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="OperatingLeaseLiabilityNoncurrent" xlink:title="OperatingLeaseLiabilityNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingLeaseLiabilityNoncurrent" xlink:title="definition: StatementLineItems to OperatingLeaseLiabilityNoncurrent" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="DeferredIncomeTaxLiabilitiesNet" xlink:title="DeferredIncomeTaxLiabilitiesNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DeferredIncomeTaxLiabilitiesNet" xlink:title="definition: StatementLineItems to DeferredIncomeTaxLiabilitiesNet" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="OtherLiabilitiesNoncurrent" xlink:title="OtherLiabilitiesNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherLiabilitiesNoncurrent" xlink:title="definition: StatementLineItems to OtherLiabilitiesNoncurrent" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Liabilities" xlink:label="Liabilities" xlink:title="Liabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="Liabilities" xlink:title="definition: StatementLineItems to Liabilities" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="CommitmentsAndContingencies" xlink:title="CommitmentsAndContingencies" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CommitmentsAndContingencies" xlink:title="definition: StatementLineItems to CommitmentsAndContingencies" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="StockholdersEquityAbstract" xlink:title="StockholdersEquityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockholdersEquityAbstract" xlink:title="definition: StatementLineItems to StockholdersEquityAbstract" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="LiabilitiesAndStockholdersEquity" xlink:title="LiabilitiesAndStockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LiabilitiesAndStockholdersEquity" xlink:title="definition: StatementLineItems to LiabilitiesAndStockholdersEquity" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockValue" xlink:label="CommonStockValue" xlink:title="CommonStockValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CommonStockValue" xlink:title="definition: StatementLineItems to CommonStockValue" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="AdditionalPaidInCapital" xlink:title="AdditionalPaidInCapital" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AdditionalPaidInCapital" xlink:title="definition: StatementLineItems to AdditionalPaidInCapital" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="RetainedEarningsAccumulatedDeficit" xlink:title="RetainedEarningsAccumulatedDeficit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="RetainedEarningsAccumulatedDeficit" xlink:title="definition: StatementLineItems to RetainedEarningsAccumulatedDeficit" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: StatementLineItems to AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="StockholdersEquity" xlink:title="StockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockholdersEquity" xlink:title="definition: StatementLineItems to StockholdersEquity" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterest" xlink:label="MinorityInterest" xlink:title="MinorityInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="MinorityInterest" xlink:title="definition: StatementLineItems to MinorityInterest" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowings" xlink:label="ShortTermBorrowings" xlink:title="ShortTermBorrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ShortTermBorrowings" xlink:title="definition: StatementLineItems to ShortTermBorrowings" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="LongTermDebtCurrent" xlink:title="LongTermDebtCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LongTermDebtCurrent" xlink:title="definition: StatementLineItems to LongTermDebtCurrent" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="AccountsPayableCurrent" xlink:title="AccountsPayableCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccountsPayableCurrent" xlink:title="definition: StatementLineItems to AccountsPayableCurrent" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="ContractWithCustomerLiabilityCurrent" xlink:title="ContractWithCustomerLiabilityCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ContractWithCustomerLiabilityCurrent" xlink:title="definition: StatementLineItems to ContractWithCustomerLiabilityCurrent" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeCurrent" xlink:label="DeferredIncomeCurrent" xlink:title="DeferredIncomeCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DeferredIncomeCurrent" xlink:title="definition: StatementLineItems to DeferredIncomeCurrent" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedIncomeTaxesCurrent" xlink:label="AccruedIncomeTaxesCurrent" xlink:title="AccruedIncomeTaxesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccruedIncomeTaxesCurrent" xlink:title="definition: StatementLineItems to AccruedIncomeTaxesCurrent" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" xlink:label="IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" xlink:title="IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" xlink:title="definition: StatementLineItems to IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAccountsPayableAndAccruedLiabilities" xlink:label="OtherAccountsPayableAndAccruedLiabilities" xlink:title="OtherAccountsPayableAndAccruedLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherAccountsPayableAndAccruedLiabilities" xlink:title="definition: StatementLineItems to OtherAccountsPayableAndAccruedLiabilities" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="OperatingLeaseLiabilityCurrent" xlink:title="OperatingLeaseLiabilityCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingLeaseLiabilityCurrent" xlink:title="definition: StatementLineItems to OperatingLeaseLiabilityCurrent" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="LiabilitiesCurrent" xlink:title="LiabilitiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LiabilitiesCurrent" xlink:title="definition: StatementLineItems to LiabilitiesCurrent" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="AssetsCurrentAbstract" xlink:title="AssetsCurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AssetsCurrentAbstract" xlink:title="definition: StatementLineItems to AssetsCurrentAbstract" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="PropertyPlantAndEquipmentNet" xlink:title="PropertyPlantAndEquipmentNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="PropertyPlantAndEquipmentNet" xlink:title="definition: StatementLineItems to PropertyPlantAndEquipmentNet" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LandUseRightNet" xlink:label="LandUseRightNet" xlink:title="LandUseRightNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LandUseRightNet" xlink:title="definition: StatementLineItems to LandUseRightNet" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="OperatingLeaseRightOfUseAsset" xlink:title="OperatingLeaseRightOfUseAsset" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingLeaseRightOfUseAsset" xlink:title="definition: StatementLineItems to OperatingLeaseRightOfUseAsset" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="FiniteLivedIntangibleAssetsNet" xlink:title="FiniteLivedIntangibleAssetsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="FiniteLivedIntangibleAssetsNet" xlink:title="definition: StatementLineItems to FiniteLivedIntangibleAssetsNet" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="DeferredIncomeTaxAssetsNet" xlink:title="DeferredIncomeTaxAssetsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DeferredIncomeTaxAssetsNet" xlink:title="definition: StatementLineItems to DeferredIncomeTaxAssetsNet" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Investments" xlink:label="Investments" xlink:title="Investments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="Investments" xlink:title="definition: StatementLineItems to Investments" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="OtherAssetsNoncurrent" xlink:title="OtherAssetsNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherAssetsNoncurrent" xlink:title="definition: StatementLineItems to OtherAssetsNoncurrent" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets" xlink:label="Assets" xlink:title="Assets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="Assets" xlink:title="definition: StatementLineItems to Assets" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="CashAndCashEquivalentsAtCarryingValue" xlink:title="CashAndCashEquivalentsAtCarryingValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CashAndCashEquivalentsAtCarryingValue" xlink:title="definition: StatementLineItems to CashAndCashEquivalentsAtCarryingValue" order="38.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MarketableSecuritiesCurrent" xlink:label="MarketableSecuritiesCurrent" xlink:title="MarketableSecuritiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="MarketableSecuritiesCurrent" xlink:title="definition: StatementLineItems to MarketableSecuritiesCurrent" order="39.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="AccountsReceivableNetCurrent" xlink:title="AccountsReceivableNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccountsReceivableNetCurrent" xlink:title="definition: StatementLineItems to AccountsReceivableNetCurrent" order="40.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesReceivable" xlink:label="IncomeTaxesReceivable" xlink:title="IncomeTaxesReceivable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeTaxesReceivable" xlink:title="definition: StatementLineItems to IncomeTaxesReceivable" order="41.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherReceivablesNetCurrent" xlink:label="OtherReceivablesNetCurrent" xlink:title="OtherReceivablesNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherReceivablesNetCurrent" xlink:title="definition: StatementLineItems to OtherReceivablesNetCurrent" order="42.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryNet" xlink:label="InventoryNet" xlink:title="InventoryNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="InventoryNet" xlink:title="definition: StatementLineItems to InventoryNet" order="43.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="PrepaidExpenseCurrent" xlink:title="PrepaidExpenseCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="PrepaidExpenseCurrent" xlink:title="definition: StatementLineItems to PrepaidExpenseCurrent" order="44.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="AssetsCurrent" xlink:title="AssetsCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AssetsCurrent" xlink:title="definition: StatementLineItems to AssetsCurrent" order="45.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="46.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: StatementTable to StatementClassOfStockAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="CommonClassBMember" xlink:title="CommonClassBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassBMember" xlink:title="definition: ClassOfStockDomain to CommonClassBMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ConsolidatedBalanceSheetsParenthetical">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="AssetsAbstract" xlink:title="AssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AssetsAbstract" xlink:title="definition: StatementLineItems to AssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="LiabilitiesAndStockholdersEquityAbstract" xlink:title="LiabilitiesAndStockholdersEquityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LiabilitiesAndStockholdersEquityAbstract" xlink:title="definition: StatementLineItems to LiabilitiesAndStockholdersEquityAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="StockholdersEquityAbstract" xlink:title="StockholdersEquityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockholdersEquityAbstract" xlink:title="definition: StatementLineItems to StockholdersEquityAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="CommonStockParOrStatedValuePerShare" xlink:title="CommonStockParOrStatedValuePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CommonStockParOrStatedValuePerShare" xlink:title="definition: StatementLineItems to CommonStockParOrStatedValuePerShare" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="CommonStockSharesAuthorized" xlink:title="CommonStockSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CommonStockSharesAuthorized" xlink:title="definition: StatementLineItems to CommonStockSharesAuthorized" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="CommonStockSharesIssued" xlink:title="CommonStockSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CommonStockSharesIssued" xlink:title="definition: StatementLineItems to CommonStockSharesIssued" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="CommonStockSharesOutstanding" xlink:title="CommonStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CommonStockSharesOutstanding" xlink:title="definition: StatementLineItems to CommonStockSharesOutstanding" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="AssetsCurrentAbstract" xlink:title="AssetsCurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AssetsCurrentAbstract" xlink:title="definition: StatementLineItems to AssetsCurrentAbstract" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:label="AllowanceForDoubtfulAccountsReceivableCurrent" xlink:title="AllowanceForDoubtfulAccountsReceivableCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AllowanceForDoubtfulAccountsReceivableCurrent" xlink:title="definition: StatementLineItems to AllowanceForDoubtfulAccountsReceivableCurrent" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="10.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: StatementTable to StatementClassOfStockAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="CommonClassBMember" xlink:title="CommonClassBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassBMember" xlink:title="definition: ClassOfStockDomain to CommonClassBMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ConsolidatedStatementsOfOperationsAndComprehensiveIncome" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ConsolidatedStatementOfChangesInStockholdersEquity">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="IncreaseDecreaseInStockholdersEquityRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="definition: StatementLineItems to IncreaseDecreaseInStockholdersEquityRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="SharesOutstanding" xlink:title="SharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="SharesOutstanding" xlink:title="definition: StatementLineItems to SharesOutstanding" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetIncomeLoss" xlink:title="definition: StatementLineItems to NetIncomeLoss" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NetIncomeExcludingRedeemableNonControllingInterest" xlink:label="NetIncomeExcludingRedeemableNonControllingInterest" xlink:title="NetIncomeExcludingRedeemableNonControllingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetIncomeExcludingRedeemableNonControllingInterest" xlink:title="definition: StatementLineItems to NetIncomeExcludingRedeemableNonControllingInterest" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:title="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:title="definition: StatementLineItems to OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="StockIssuedDuringPeriodValueStockOptionsExercised" xlink:title="StockIssuedDuringPeriodValueStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueStockOptionsExercised" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueStockOptionsExercised" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesStockOptionsExercised" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited" xlink:label="StockIssuedDuringPeriodValueShareBasedCompensationForfeited" xlink:title="StockIssuedDuringPeriodValueShareBasedCompensationForfeited" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueShareBasedCompensationForfeited" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueShareBasedCompensationForfeited" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="definition: StatementLineItems to AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="StockIssuedDuringPeriodValueNewIssues" xlink:title="StockIssuedDuringPeriodValueNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueNewIssues" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueNewIssues" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="StockIssuedDuringPeriodSharesNewIssues" xlink:title="StockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesNewIssues" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesNewIssues" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="StockRepurchasedDuringPeriodValue" xlink:title="StockRepurchasedDuringPeriodValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockRepurchasedDuringPeriodValue" xlink:title="definition: StatementLineItems to StockRepurchasedDuringPeriodValue" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="StockRepurchasedDuringPeriodShares" xlink:title="StockRepurchasedDuringPeriodShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockRepurchasedDuringPeriodShares" xlink:title="definition: StatementLineItems to StockRepurchasedDuringPeriodShares" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfUnits" xlink:label="StockIssuedDuringPeriodValueConversionOfUnits" xlink:title="StockIssuedDuringPeriodValueConversionOfUnits" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueConversionOfUnits" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueConversionOfUnits" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:label="StockIssuedDuringPeriodSharesConversionOfUnits" xlink:title="StockIssuedDuringPeriodSharesConversionOfUnits" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesConversionOfUnits" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesConversionOfUnits" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="StockRepurchasedAndRetiredDuringPeriodValue" xlink:title="StockRepurchasedAndRetiredDuringPeriodValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockRepurchasedAndRetiredDuringPeriodValue" xlink:title="definition: StatementLineItems to StockRepurchasedAndRetiredDuringPeriodValue" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="StockRepurchasedAndRetiredDuringPeriodShares" xlink:title="StockRepurchasedAndRetiredDuringPeriodShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockRepurchasedAndRetiredDuringPeriodShares" xlink:title="definition: StatementLineItems to StockRepurchasedAndRetiredDuringPeriodShares" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:label="AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:title="AdjustmentsToAdditionalPaidInCapitalWarrantIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:title="definition: StatementLineItems to AdjustmentsToAdditionalPaidInCapitalWarrantIssued" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_StockIssuedDuringPeriodValueCommonStockWarrantExercised" xlink:label="StockIssuedDuringPeriodValueCommonStockWarrantExercised" xlink:title="StockIssuedDuringPeriodValueCommonStockWarrantExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueCommonStockWarrantExercised" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueCommonStockWarrantExercised" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:label="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:title="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesCommonStockWarrantExercised" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ReclassificationOfRedeemableNonControllingInterest" xlink:label="ReclassificationOfRedeemableNonControllingInterest" xlink:title="ReclassificationOfRedeemableNonControllingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ReclassificationOfRedeemableNonControllingInterest" xlink:title="definition: StatementLineItems to ReclassificationOfRedeemableNonControllingInterest" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiaryEquityIssuedDuringPeriodValueNetOfIssuanceCosts" xlink:label="SubsidiaryEquityIssuedDuringPeriodValueNetOfIssuanceCosts" xlink:title="SubsidiaryEquityIssuedDuringPeriodValueNetOfIssuanceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="SubsidiaryEquityIssuedDuringPeriodValueNetOfIssuanceCosts" xlink:title="definition: StatementLineItems to SubsidiaryEquityIssuedDuringPeriodValueNetOfIssuanceCosts" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiaryEquityIssuedDuringPeriodShares" xlink:label="SubsidiaryEquityIssuedDuringPeriodShares" xlink:title="SubsidiaryEquityIssuedDuringPeriodShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="SubsidiaryEquityIssuedDuringPeriodShares" xlink:title="definition: StatementLineItems to SubsidiaryEquityIssuedDuringPeriodShares" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="25.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: StatementTable to StatementEquityComponentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="CommonStockMember" xlink:title="definition: EquityComponentDomain to CommonStockMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="AdditionalPaidInCapitalMember" xlink:title="AdditionalPaidInCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AdditionalPaidInCapitalMember" xlink:title="definition: EquityComponentDomain to AdditionalPaidInCapitalMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="RetainedEarningsMember" xlink:title="RetainedEarningsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="RetainedEarningsMember" xlink:title="definition: EquityComponentDomain to RetainedEarningsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: EquityComponentDomain to AccumulatedOtherComprehensiveIncomeMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="NoncontrollingInterestMember" xlink:title="NoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="NoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to NoncontrollingInterestMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: StatementTable to StatementClassOfStockAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="CommonClassBMember" xlink:title="CommonClassBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassBMember" xlink:title="definition: ClassOfStockDomain to CommonClassBMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ConsolidatedStatementsOfCashFlows" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ConsolidatedStatementsOfCashFlowsParenthetical" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/DescriptionOfBusiness" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RevenueFromContractsWithCustomers" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/AccountsReceivable" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/Inventories" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/PropertyPlantAndEquipmentNet" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LandUseRightNet" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherLongtermAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ShorttermBorrowings" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherPayableAndAccruedExpenses" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/Leases" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LongtermBorrowings" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherLongtermLiabilities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LongtermInvestment" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/FinancialLiabilityCarriedAtFairValue" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/TradingSecurities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RelatedPartyBalancesAndTransactions" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/CommonStock" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RedeemableNoncontrollingInterests" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/StockbasedCompensation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/IncomeTaxes" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SegmentInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/CommitmentsAndContingencies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RestrictedNetAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/DescriptionOfBusinessTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RevenueFromContractsWithCustomersTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/AccountsReceivableTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/InventoriesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/PropertyPlantAndEquipmentNetTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LandUseRightNetTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherLongtermAssetsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ShorttermBorrowingsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherPayableAndAccruedExpensesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LeasesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LongtermBorrowingsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherLongtermLiabilitiesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LongtermInvestmentTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/FinancialLiabilityCarriedAtFairValueTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/TradingSecuritiesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RelatedPartyBalancesAndTransactionsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RedeemableNoncontrollingInterestsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/StockbasedCompensationTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:label="ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:title="ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:label="ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:title="ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:title="ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:label="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:title="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to ShareBasedPaymentArrangementNonEmployeeStockOptionMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to ConsolidatedEntitiesAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SubsidiariesMember" xlink:label="SubsidiariesMember" xlink:title="SubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="SubsidiariesMember" xlink:title="definition: ConsolidatedEntitiesDomain to SubsidiariesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchShanghaiIncMember" xlink:label="ACMResearchShanghaiIncMember" xlink:title="ACMResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchShanghaiIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/IncomeTaxesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/DescriptionOfBusinessDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_BusinessDescriptionAbstract" xlink:label="BusinessDescriptionAbstract" xlink:title="BusinessDescriptionAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="BusinessDescriptionAbstract" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to BusinessDescriptionAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_BusinessAcquisitionPercentageOfEquityInterestsAcquired" xlink:label="BusinessAcquisitionPercentageOfEquityInterestsAcquired" xlink:title="BusinessAcquisitionPercentageOfEquityInterestsAcquired" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="BusinessAcquisitionPercentageOfEquityInterestsAcquired" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to BusinessAcquisitionPercentageOfEquityInterestsAcquired" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries" xlink:label="ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries" xlink:title="ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityNoteStockSplitConversionRatio1" xlink:label="StockholdersEquityNoteStockSplitConversionRatio1" xlink:title="StockholdersEquityNoteStockSplitConversionRatio1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="StockholdersEquityNoteStockSplitConversionRatio1" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to StockholdersEquityNoteStockSplitConversionRatio1" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_TermToCompleteListingOfShares" xlink:label="TermToCompleteListingOfShares" xlink:title="TermToCompleteListingOfShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="TermToCompleteListingOfShares" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to TermToCompleteListingOfShares" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NameOfSubsidiary" xlink:label="NameOfSubsidiary" xlink:title="NameOfSubsidiary" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="NameOfSubsidiary" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to NameOfSubsidiary" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NameOfDateOfIncorporation" xlink:label="NameOfDateOfIncorporation" xlink:title="NameOfDateOfIncorporation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="NameOfDateOfIncorporation" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to NameOfDateOfIncorporation" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiariesOwnershipPercentage" xlink:label="SubsidiariesOwnershipPercentage" xlink:title="SubsidiariesOwnershipPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="SubsidiariesOwnershipPercentage" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to SubsidiariesOwnershipPercentage" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="StockIssuedDuringPeriodSharesNewIssues" xlink:title="StockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="StockIssuedDuringPeriodSharesNewIssues" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to StockIssuedDuringPeriodSharesNewIssues" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_PercentageAmountOfSharesOfferedFromSharesOutstanding" xlink:label="PercentageAmountOfSharesOfferedFromSharesOutstanding" xlink:title="PercentageAmountOfSharesOfferedFromSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="PercentageAmountOfSharesOfferedFromSharesOutstanding" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to PercentageAmountOfSharesOfferedFromSharesOutstanding" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="CommonStockSharesOutstanding" xlink:title="CommonStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="CommonStockSharesOutstanding" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to CommonStockSharesOutstanding" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockPricePerShare" xlink:label="SaleOfStockPricePerShare" xlink:title="SaleOfStockPricePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="SaleOfStockPricePerShare" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to SaleOfStockPricePerShare" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="ProceedsFromIssuanceInitialPublicOffering" xlink:title="ProceedsFromIssuanceInitialPublicOffering" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ProceedsFromIssuanceInitialPublicOffering" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ProceedsFromIssuanceInitialPublicOffering" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction" xlink:label="SaleOfStockPercentageOfOwnershipAfterTransaction" xlink:title="SaleOfStockPercentageOfOwnershipAfterTransaction" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="SaleOfStockPercentageOfOwnershipAfterTransaction" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to SaleOfStockPercentageOfOwnershipAfterTransaction" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" order="15.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable to ConsolidatedEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SubsidiariesMember" xlink:label="SubsidiariesMember" xlink:title="SubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="SubsidiariesMember" xlink:title="definition: ConsolidatedEntitiesDomain to SubsidiariesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchShanghaiIncMember" xlink:label="ACMResearchShanghaiIncMember" xlink:title="ACMResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchShanghaiIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchWuxiIncMember" xlink:label="ACMResearchWuxiIncMember" xlink:title="ACMResearchWuxiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchWuxiIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchWuxiIncMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CleanChipTechnologiesLimitedMember" xlink:label="CleanChipTechnologiesLimitedMember" xlink:title="CleanChipTechnologiesLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="CleanChipTechnologiesLimitedMember" xlink:title="definition: SubsidiariesMember to CleanChipTechnologiesLimitedMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchKoreaCOLTDMember" xlink:label="ACMResearchKoreaCOLTDMember" xlink:title="ACMResearchKoreaCOLTDMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchKoreaCOLTDMember" xlink:title="definition: SubsidiariesMember to ACMResearchKoreaCOLTDMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShengweiResearchShanghaiIncMember" xlink:label="ShengweiResearchShanghaiIncMember" xlink:title="ShengweiResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ShengweiResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ShengweiResearchShanghaiIncMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchCAIncMember" xlink:label="ACMResearchCAIncMember" xlink:title="ACMResearchCAIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchCAIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchCAIncMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchCaymanIncMember" xlink:label="ACMResearchCaymanIncMember" xlink:title="ACMResearchCaymanIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchCaymanIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchCaymanIncMember" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchSingaporePTELTDMember" xlink:label="ACMResearchSingaporePTELTDMember" xlink:title="ACMResearchSingaporePTELTDMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchSingaporePTELTDMember" xlink:title="definition: SubsidiariesMember to ACMResearchSingaporePTELTDMember" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="SubsidiarySaleOfStockAxis" xlink:title="SubsidiarySaleOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:to="SubsidiarySaleOfStockAxis" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable to SubsidiarySaleOfStockAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain_2" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain_2" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IPOMember" xlink:label="IPOMember" xlink:title="IPOMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="IPOMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to IPOMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable to StatementClassOfStockAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="CommonClassBMember" xlink:title="CommonClassBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassBMember" xlink:title="definition: ClassOfStockDomain to CommonClassBMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesRestrictedCashDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesAccountsReceivableDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesLandUseRightsNetDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesInventoryDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesPropertyPlantAndEquipmentNetDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGrossAbstract" xlink:label="PropertyPlantAndEquipmentGrossAbstract" xlink:title="PropertyPlantAndEquipmentGrossAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentGrossAbstract" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentGrossAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="PropertyPlantAndEquipmentUsefulLife" xlink:title="PropertyPlantAndEquipmentUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentUsefulLife" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentUsefulLife" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ComputerAndOfficeEquipmentMember" xlink:label="ComputerAndOfficeEquipmentMember" xlink:title="ComputerAndOfficeEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="ComputerAndOfficeEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to ComputerAndOfficeEquipmentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ManufacturingEquipmentMember" xlink:label="ManufacturingEquipmentMember" xlink:title="ManufacturingEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="ManufacturingEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to ManufacturingEquipmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="FurnitureAndFixturesMember" xlink:title="FurnitureAndFixturesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="FurnitureAndFixturesMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to FurnitureAndFixturesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransportationEquipmentMember" xlink:label="TransportationEquipmentMember" xlink:title="TransportationEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="TransportationEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to TransportationEquipmentMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ElectronicEquipmentMember" xlink:label="ElectronicEquipmentMember" xlink:title="ElectronicEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="ElectronicEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to ElectronicEquipmentMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="LeaseholdImprovementsMember" xlink:title="LeaseholdImprovementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="LeaseholdImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to LeaseholdImprovementsMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to StatementGeographicalAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="US" xlink:title="definition: SegmentGeographicalDomain to US" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_CN" xlink:label="CN" xlink:title="CN" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="CN" xlink:title="definition: SegmentGeographicalDomain to CN" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to RangeAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesIntangibleAssetsNetDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="FiniteLivedIntangibleAssetsLineItems" xlink:title="FiniteLivedIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract" xlink:label="FiniteLivedIntangibleAssetsNetAbstract" xlink:title="FiniteLivedIntangibleAssetsNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsNetAbstract" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsNetAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IntangibleAssetsAmortizationPeriodCondition" xlink:label="IntangibleAssetsAmortizationPeriodCondition" xlink:title="IntangibleAssetsAmortizationPeriodCondition" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="IntangibleAssetsAmortizationPeriodCondition" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to IntangibleAssetsAmortizationPeriodCondition" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:label="FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:title="FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="ScheduleOfFiniteLivedIntangibleAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to ScheduleOfFiniteLivedIntangibleAssetsTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to RangeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to FiniteLivedIntangibleAssetsByMajorClassAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="ComputerSoftwareIntangibleAssetMember" xlink:title="ComputerSoftwareIntangibleAssetMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="ComputerSoftwareIntangibleAssetMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to ComputerSoftwareIntangibleAssetMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesShippingAndHandlingCostsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedIncomeStatementsCaptionsLineItems" xlink:label="CondensedIncomeStatementsCaptionsLineItems" xlink:title="CondensedIncomeStatementsCaptionsLineItems" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShippingAndHandlingCostsAbstract" xlink:label="ShippingAndHandlingCostsAbstract" xlink:title="ShippingAndHandlingCostsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="ShippingAndHandlingCostsAbstract" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to ShippingAndHandlingCostsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="SellingAndMarketingExpense" xlink:title="SellingAndMarketingExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="SellingAndMarketingExpense" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to SellingAndMarketingExpense" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedIncomeStatementTable" xlink:label="CondensedIncomeStatementTable" xlink:title="CondensedIncomeStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="CondensedIncomeStatementTable" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to CondensedIncomeStatementTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="ProductOrServiceAxis" xlink:title="ProductOrServiceAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="CondensedIncomeStatementTable" xlink:to="ProductOrServiceAxis" xlink:title="definition: CondensedIncomeStatementTable to ProductOrServiceAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShippingAndHandlingMember" xlink:label="ShippingAndHandlingMember" xlink:title="ShippingAndHandlingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="ShippingAndHandlingMember" xlink:title="definition: ProductsAndServicesDomain to ShippingAndHandlingMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesWarrantyDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductWarrantyLiabilityLineItems" xlink:label="ProductWarrantyLiabilityLineItems" xlink:title="ProductWarrantyLiabilityLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StandardProductWarrantyDisclosureAbstract" xlink:label="StandardProductWarrantyDisclosureAbstract" xlink:title="StandardProductWarrantyDisclosureAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductWarrantyLiabilityLineItems" xlink:to="StandardProductWarrantyDisclosureAbstract" xlink:title="definition: ProductWarrantyLiabilityLineItems to StandardProductWarrantyDisclosureAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_StandardProductWarrantyPeriod" xlink:label="StandardProductWarrantyPeriod" xlink:title="StandardProductWarrantyPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductWarrantyLiabilityLineItems" xlink:to="StandardProductWarrantyPeriod" xlink:title="definition: ProductWarrantyLiabilityLineItems to StandardProductWarrantyPeriod" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_WarrantyObligationsRollForward" xlink:label="WarrantyObligationsRollForward" xlink:title="WarrantyObligationsRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductWarrantyLiabilityLineItems" xlink:to="WarrantyObligationsRollForward" xlink:title="definition: ProductWarrantyLiabilityLineItems to WarrantyObligationsRollForward" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductWarrantyAccrualClassifiedCurrent" xlink:label="ProductWarrantyAccrualClassifiedCurrent" xlink:title="ProductWarrantyAccrualClassifiedCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductWarrantyLiabilityLineItems" xlink:to="ProductWarrantyAccrualClassifiedCurrent" xlink:title="definition: ProductWarrantyLiabilityLineItems to ProductWarrantyAccrualClassifiedCurrent" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ProductWarrantyAccrualAdditions" xlink:label="ProductWarrantyAccrualAdditions" xlink:title="ProductWarrantyAccrualAdditions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductWarrantyLiabilityLineItems" xlink:to="ProductWarrantyAccrualAdditions" xlink:title="definition: ProductWarrantyLiabilityLineItems to ProductWarrantyAccrualAdditions" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ProductWarrantyAccrualUtilized" xlink:label="ProductWarrantyAccrualUtilized" xlink:title="ProductWarrantyAccrualUtilized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductWarrantyLiabilityLineItems" xlink:to="ProductWarrantyAccrualUtilized" xlink:title="definition: ProductWarrantyLiabilityLineItems to ProductWarrantyAccrualUtilized" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductWarrantyLiabilityTable" xlink:label="ProductWarrantyLiabilityTable" xlink:title="ProductWarrantyLiabilityTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ProductWarrantyLiabilityLineItems" xlink:to="ProductWarrantyLiabilityTable" xlink:title="definition: ProductWarrantyLiabilityLineItems to ProductWarrantyLiabilityTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ProductWarrantyLiabilityTable" xlink:to="RangeAxis" xlink:title="definition: ProductWarrantyLiabilityTable to RangeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesGovernmentSubsidiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesBasicAndDilutedNetIncomePerCommonShareDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesComprehensiveIncomeAttributableToCompanyDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesStatutoryReservesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:title="AccumulatedOtherComprehensiveIncomeLossLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficitAbstract" xlink:label="RetainedEarningsAccumulatedDeficitAbstract" xlink:title="RetainedEarningsAccumulatedDeficitAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="RetainedEarningsAccumulatedDeficitAbstract" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to RetainedEarningsAccumulatedDeficitAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" xlink:label="StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" xlink:title="StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="AccumulatedOtherComprehensiveIncomeLossTable" xlink:title="AccumulatedOtherComprehensiveIncomeLossTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossTable" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to AccumulatedOtherComprehensiveIncomeLossTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="AccumulatedOtherComprehensiveIncomeLossTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossTable to ConsolidatedEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SubsidiariesMember" xlink:label="SubsidiariesMember" xlink:title="SubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="SubsidiariesMember" xlink:title="definition: ConsolidatedEntitiesDomain to SubsidiariesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchShanghaiIncMember" xlink:label="ACMResearchShanghaiIncMember" xlink:title="ACMResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchShanghaiIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SummaryOfSignificantAccountingPoliciesOperatingAndFinancialRisksDetails">
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_TranslationsOfForeignExchangeRatesLineItems" xlink:label="TranslationsOfForeignExchangeRatesLineItems" xlink:title="TranslationsOfForeignExchangeRatesLineItems" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_TranslationsOfForeignExchangeRateAbstract" xlink:label="TranslationsOfForeignExchangeRateAbstract" xlink:title="TranslationsOfForeignExchangeRateAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TranslationsOfForeignExchangeRatesLineItems" xlink:to="TranslationsOfForeignExchangeRateAbstract" xlink:title="definition: TranslationsOfForeignExchangeRatesLineItems to TranslationsOfForeignExchangeRateAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="StatementOfFinancialPositionAbstract" xlink:title="StatementOfFinancialPositionAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TranslationsOfForeignExchangeRatesLineItems" xlink:to="StatementOfFinancialPositionAbstract" xlink:title="definition: TranslationsOfForeignExchangeRatesLineItems to StatementOfFinancialPositionAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="IncomeStatementAbstract" xlink:title="IncomeStatementAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TranslationsOfForeignExchangeRatesLineItems" xlink:to="IncomeStatementAbstract" xlink:title="definition: TranslationsOfForeignExchangeRatesLineItems to IncomeStatementAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ForeignCurrencyExchangeRateTranslation2" xlink:label="ForeignCurrencyExchangeRateTranslation2" xlink:title="ForeignCurrencyExchangeRateTranslation2" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TranslationsOfForeignExchangeRatesLineItems" xlink:to="ForeignCurrencyExchangeRateTranslation2" xlink:title="definition: TranslationsOfForeignExchangeRatesLineItems to ForeignCurrencyExchangeRateTranslation2" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCurrencyExchangeRateTranslation1" xlink:label="ForeignCurrencyExchangeRateTranslation1" xlink:title="ForeignCurrencyExchangeRateTranslation1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TranslationsOfForeignExchangeRatesLineItems" xlink:to="ForeignCurrencyExchangeRateTranslation1" xlink:title="definition: TranslationsOfForeignExchangeRatesLineItems to ForeignCurrencyExchangeRateTranslation1" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ScheduleOfTranslationsOfForeignExchangeRateTable" xlink:label="ScheduleOfTranslationsOfForeignExchangeRateTable" xlink:title="ScheduleOfTranslationsOfForeignExchangeRateTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="TranslationsOfForeignExchangeRatesLineItems" xlink:to="ScheduleOfTranslationsOfForeignExchangeRateTable" xlink:title="definition: TranslationsOfForeignExchangeRatesLineItems to ScheduleOfTranslationsOfForeignExchangeRateTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CurrencyAxis" xlink:label="CurrencyAxis" xlink:title="CurrencyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfTranslationsOfForeignExchangeRateTable" xlink:to="CurrencyAxis" xlink:title="definition: ScheduleOfTranslationsOfForeignExchangeRateTable to CurrencyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2021/currency-2021.xsd#currency_AllCurrenciesDomain" xlink:label="AllCurrenciesDomain" xlink:title="AllCurrenciesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CurrencyAxis" xlink:to="AllCurrenciesDomain" xlink:title="definition: CurrencyAxis to AllCurrenciesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2021/currency-2021.xsd#currency_AllCurrenciesDomain" xlink:label="AllCurrenciesDomain_2" xlink:title="AllCurrenciesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CurrencyAxis" xlink:to="AllCurrenciesDomain_2" xlink:title="definition: CurrencyAxis to AllCurrenciesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2021/currency-2021.xsd#currency_CNY" xlink:label="CNY" xlink:title="CNY" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="CNY" xlink:title="definition: AllCurrenciesDomain to CNY" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2021/currency-2021.xsd#currency_KRW" xlink:label="KRW" xlink:title="KRW" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="KRW" xlink:title="definition: AllCurrenciesDomain to KRW" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="ConcentrationRiskLineItems" xlink:title="ConcentrationRiskLineItems" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ConcentrationOfCreditRiskAbstract" xlink:label="ConcentrationOfCreditRiskAbstract" xlink:title="ConcentrationOfCreditRiskAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationOfCreditRiskAbstract" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationOfCreditRiskAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NumberOfMajorCustomers" xlink:label="NumberOfMajorCustomers" xlink:title="NumberOfMajorCustomers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskLineItems" xlink:to="NumberOfMajorCustomers" xlink:title="definition: ConcentrationRiskLineItems to NumberOfMajorCustomers" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="ConcentrationRiskPercentage1" xlink:title="ConcentrationRiskPercentage1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskPercentage1" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskPercentage1" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="ConcentrationRiskTable" xlink:title="ConcentrationRiskTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskTable" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis" xlink:label="MajorCustomersAxis" xlink:title="MajorCustomersAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="MajorCustomersAxis" xlink:title="definition: ConcentrationRiskTable to MajorCustomersAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="NameOfMajorCustomerDomain" xlink:title="NameOfMajorCustomerDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="MajorCustomersAxis" xlink:to="NameOfMajorCustomerDomain" xlink:title="definition: MajorCustomersAxis to NameOfMajorCustomerDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="NameOfMajorCustomerDomain_2" xlink:title="NameOfMajorCustomerDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MajorCustomersAxis" xlink:to="NameOfMajorCustomerDomain_2" xlink:title="definition: MajorCustomersAxis to NameOfMajorCustomerDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CustomerMember" xlink:label="CustomerMember" xlink:title="CustomerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NameOfMajorCustomerDomain" xlink:to="CustomerMember" xlink:title="definition: NameOfMajorCustomerDomain to CustomerMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CustomerAMember" xlink:label="CustomerAMember" xlink:title="CustomerAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CustomerMember" xlink:to="CustomerAMember" xlink:title="definition: CustomerMember to CustomerAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CustomerBMember" xlink:label="CustomerBMember" xlink:title="CustomerBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CustomerMember" xlink:to="CustomerBMember" xlink:title="definition: CustomerMember to CustomerBMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CustomerCMember" xlink:label="CustomerCMember" xlink:title="CustomerCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CustomerMember" xlink:to="CustomerCMember" xlink:title="definition: CustomerMember to CustomerCMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CustomerDMember" xlink:label="CustomerDMember" xlink:title="CustomerDMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CustomerMember" xlink:to="CustomerDMember" xlink:title="definition: CustomerMember to CustomerDMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="ConcentrationRiskByBenchmarkAxis" xlink:title="ConcentrationRiskByBenchmarkAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByBenchmarkAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByBenchmarkAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="ConcentrationRiskBenchmarkDomain" xlink:title="ConcentrationRiskBenchmarkDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByBenchmarkAxis" xlink:to="ConcentrationRiskBenchmarkDomain" xlink:title="definition: ConcentrationRiskByBenchmarkAxis to ConcentrationRiskBenchmarkDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="ConcentrationRiskBenchmarkDomain_2" xlink:title="ConcentrationRiskBenchmarkDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConcentrationRiskByBenchmarkAxis" xlink:to="ConcentrationRiskBenchmarkDomain_2" xlink:title="definition: ConcentrationRiskByBenchmarkAxis to ConcentrationRiskBenchmarkDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="SalesRevenueNetMember" xlink:title="SalesRevenueNetMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskBenchmarkDomain" xlink:to="SalesRevenueNetMember" xlink:title="definition: ConcentrationRiskBenchmarkDomain to SalesRevenueNetMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="ConcentrationRiskByTypeAxis" xlink:title="ConcentrationRiskByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByTypeAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByTypeAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="ConcentrationRiskTypeDomain" xlink:title="ConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByTypeAxis" xlink:to="ConcentrationRiskTypeDomain" xlink:title="definition: ConcentrationRiskByTypeAxis to ConcentrationRiskTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="ConcentrationRiskTypeDomain_2" xlink:title="ConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConcentrationRiskByTypeAxis" xlink:to="ConcentrationRiskTypeDomain_2" xlink:title="definition: ConcentrationRiskByTypeAxis to ConcentrationRiskTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="CustomerConcentrationRiskMember" xlink:title="CustomerConcentrationRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskTypeDomain" xlink:to="CustomerConcentrationRiskMember" xlink:title="definition: ConcentrationRiskTypeDomain to CustomerConcentrationRiskMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RevenueFromContractsWithCustomersDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="DisaggregationOfRevenueLineItems" xlink:title="DisaggregationOfRevenueLineItems" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_DisaggregatedRevenueInformationAbstract" xlink:label="DisaggregatedRevenueInformationAbstract" xlink:title="DisaggregatedRevenueInformationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="DisaggregatedRevenueInformationAbstract" xlink:title="definition: DisaggregationOfRevenueLineItems to DisaggregatedRevenueInformationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="definition: DisaggregationOfRevenueLineItems to RevenueFromContractWithCustomerExcludingAssessedTax" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="DisaggregationOfRevenueTable" xlink:title="DisaggregationOfRevenueTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="DisaggregationOfRevenueTable" xlink:title="definition: DisaggregationOfRevenueLineItems to DisaggregationOfRevenueTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="ProductOrServiceAxis" xlink:title="ProductOrServiceAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisaggregationOfRevenueTable" xlink:to="ProductOrServiceAxis" xlink:title="definition: DisaggregationOfRevenueTable to ProductOrServiceAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_TotalSingleWaferAndSemiCriticalCleaningEquipmentMember" xlink:label="TotalSingleWaferAndSemiCriticalCleaningEquipmentMember" xlink:title="TotalSingleWaferAndSemiCriticalCleaningEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TotalSingleWaferAndSemiCriticalCleaningEquipmentMember" xlink:title="definition: ProductsAndServicesDomain to TotalSingleWaferAndSemiCriticalCleaningEquipmentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ECPFrontEndAndPackagingFurnaceAndOtherTechnologiesMember" xlink:label="ECPFrontEndAndPackagingFurnaceAndOtherTechnologiesMember" xlink:title="ECPFrontEndAndPackagingFurnaceAndOtherTechnologiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="ECPFrontEndAndPackagingFurnaceAndOtherTechnologiesMember" xlink:title="definition: ProductsAndServicesDomain to ECPFrontEndAndPackagingFurnaceAndOtherTechnologiesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_AdvancedPackagingExcludeECPServicesSparesMember" xlink:label="AdvancedPackagingExcludeECPServicesSparesMember" xlink:title="AdvancedPackagingExcludeECPServicesSparesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="AdvancedPackagingExcludeECPServicesSparesMember" xlink:title="definition: ProductsAndServicesDomain to AdvancedPackagingExcludeECPServicesSparesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_WetCleaningAndOtherFrontEndProcessingToolsMember" xlink:label="WetCleaningAndOtherFrontEndProcessingToolsMember" xlink:title="WetCleaningAndOtherFrontEndProcessingToolsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="WetCleaningAndOtherFrontEndProcessingToolsMember" xlink:title="definition: ProductsAndServicesDomain to WetCleaningAndOtherFrontEndProcessingToolsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_AdvancedPackagingOtherProcessingServicesAndSparesMember" xlink:label="AdvancedPackagingOtherProcessingServicesAndSparesMember" xlink:title="AdvancedPackagingOtherProcessingServicesAndSparesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="AdvancedPackagingOtherProcessingServicesAndSparesMember" xlink:title="definition: ProductsAndServicesDomain to AdvancedPackagingOtherProcessingServicesAndSparesMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisaggregationOfRevenueTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: DisaggregationOfRevenueTable to StatementGeographicalAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_CN" xlink:label="CN" xlink:title="CN" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="CN" xlink:title="definition: SegmentGeographicalDomain to CN" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_OherRegionsMember" xlink:label="OherRegionsMember" xlink:title="OherRegionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="OherRegionsMember" xlink:title="definition: SegmentGeographicalDomain to OherRegionsMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/AccountsReceivableDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/InventoriesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryLineItems" xlink:label="InventoryLineItems" xlink:title="InventoryLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryNetAbstract" xlink:label="InventoryNetAbstract" xlink:title="InventoryNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InventoryLineItems" xlink:to="InventoryNetAbstract" xlink:title="definition: InventoryLineItems to InventoryNetAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryRawMaterials" xlink:label="InventoryRawMaterials" xlink:title="InventoryRawMaterials" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InventoryLineItems" xlink:to="InventoryRawMaterials" xlink:title="definition: InventoryLineItems to InventoryRawMaterials" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryWorkInProcess" xlink:label="InventoryWorkInProcess" xlink:title="InventoryWorkInProcess" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InventoryLineItems" xlink:to="InventoryWorkInProcess" xlink:title="definition: InventoryLineItems to InventoryWorkInProcess" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryFinishedGoods" xlink:label="InventoryFinishedGoods" xlink:title="InventoryFinishedGoods" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InventoryLineItems" xlink:to="InventoryFinishedGoods" xlink:title="definition: InventoryLineItems to InventoryFinishedGoods" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryGross" xlink:label="InventoryGross" xlink:title="InventoryGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InventoryLineItems" xlink:to="InventoryGross" xlink:title="definition: InventoryLineItems to InventoryGross" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryValuationReserves" xlink:label="InventoryValuationReserves" xlink:title="InventoryValuationReserves" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InventoryLineItems" xlink:to="InventoryValuationReserves" xlink:title="definition: InventoryLineItems to InventoryValuationReserves" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryCurrentTable" xlink:label="InventoryCurrentTable" xlink:title="InventoryCurrentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="InventoryLineItems" xlink:to="InventoryCurrentTable" xlink:title="definition: InventoryLineItems to InventoryCurrentTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInventoryAxis" xlink:label="PublicUtilitiesInventoryAxis" xlink:title="PublicUtilitiesInventoryAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="InventoryCurrentTable" xlink:to="PublicUtilitiesInventoryAxis" xlink:title="definition: InventoryCurrentTable to PublicUtilitiesInventoryAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInventoryTypeDomain" xlink:label="PublicUtilitiesInventoryTypeDomain" xlink:title="PublicUtilitiesInventoryTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PublicUtilitiesInventoryAxis" xlink:to="PublicUtilitiesInventoryTypeDomain" xlink:title="definition: PublicUtilitiesInventoryAxis to PublicUtilitiesInventoryTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesInventoryTypeDomain" xlink:label="PublicUtilitiesInventoryTypeDomain_2" xlink:title="PublicUtilitiesInventoryTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PublicUtilitiesInventoryAxis" xlink:to="PublicUtilitiesInventoryTypeDomain_2" xlink:title="definition: PublicUtilitiesInventoryAxis to PublicUtilitiesInventoryTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_FirstToolsMember" xlink:label="FirstToolsMember" xlink:title="FirstToolsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PublicUtilitiesInventoryTypeDomain" xlink:to="FirstToolsMember" xlink:title="definition: PublicUtilitiesInventoryTypeDomain to FirstToolsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ContractualObligationMember" xlink:label="ContractualObligationMember" xlink:title="ContractualObligationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PublicUtilitiesInventoryTypeDomain" xlink:to="ContractualObligationMember" xlink:title="definition: PublicUtilitiesInventoryTypeDomain to ContractualObligationMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/PropertyPlantAndEquipmentNetDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract" xlink:label="PropertyPlantAndEquipmentNetByTypeAbstract" xlink:title="PropertyPlantAndEquipmentNetByTypeAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentNetByTypeAbstract" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentNetByTypeAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="PropertyPlantAndEquipmentGross" xlink:title="PropertyPlantAndEquipmentGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentGross" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentGross" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="definition: PropertyPlantAndEquipmentLineItems to AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionInProgressGross" xlink:label="ConstructionInProgressGross" xlink:title="ConstructionInProgressGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ConstructionInProgressGross" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ConstructionInProgressGross" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="PropertyPlantAndEquipmentNet" xlink:title="PropertyPlantAndEquipmentNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentNet" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentNet" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquipmentMember" xlink:label="EquipmentMember" xlink:title="EquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="EquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to EquipmentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OfficeEquipmentMember" xlink:label="OfficeEquipmentMember" xlink:title="OfficeEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="OfficeEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to OfficeEquipmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransportationEquipmentMember" xlink:label="TransportationEquipmentMember" xlink:title="TransportationEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="TransportationEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to TransportationEquipmentMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="LeaseholdImprovementsMember" xlink:title="LeaseholdImprovementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="LeaseholdImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to LeaseholdImprovementsMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LandUseRightNetDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LandUseRightAbstract" xlink:label="LandUseRightAbstract" xlink:title="LandUseRightAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="LandUseRightAbstract" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to LandUseRightAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_RightToUseLandLeaseTerm" xlink:label="RightToUseLandLeaseTerm" xlink:title="RightToUseLandLeaseTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="RightToUseLandLeaseTerm" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to RightToUseLandLeaseTerm" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_AreaOfSquareFootForDevelopmentAndProductionCenter" xlink:label="AreaOfSquareFootForDevelopmentAndProductionCenter" xlink:title="AreaOfSquareFootForDevelopmentAndProductionCenter" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="AreaOfSquareFootForDevelopmentAndProductionCenter" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to AreaOfSquareFootForDevelopmentAndProductionCenter" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:label="AdjustmentForAmortization" xlink:title="AdjustmentForAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="AdjustmentForAmortization" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to AdjustmentForAmortization" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LandUseRightPurchaseAmount" xlink:label="LandUseRightPurchaseAmount" xlink:title="LandUseRightPurchaseAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="LandUseRightPurchaseAmount" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to LandUseRightPurchaseAmount" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LandUseRightAccumulatedAmortization" xlink:label="LandUseRightAccumulatedAmortization" xlink:title="LandUseRightAccumulatedAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="LandUseRightAccumulatedAmortization" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to LandUseRightAccumulatedAmortization" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LandUseRightNet" xlink:label="LandUseRightNet" xlink:title="LandUseRightNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="LandUseRightNet" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to LandUseRightNet" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable to ConsolidatedEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SubsidiariesMember" xlink:label="SubsidiariesMember" xlink:title="SubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="SubsidiariesMember" xlink:title="definition: ConsolidatedEntitiesDomain to SubsidiariesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShengweiResearchShanghaiIncMember" xlink:label="ShengweiResearchShanghaiIncMember" xlink:title="ShengweiResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ShengweiResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ShengweiResearchShanghaiIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherLongtermAssetsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ShorttermBorrowingsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="ShortTermDebtLineItems" xlink:title="ShortTermDebtLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtLongtermAndShorttermCombinedAmountAbstract" xlink:label="DebtLongtermAndShorttermCombinedAmountAbstract" xlink:title="DebtLongtermAndShorttermCombinedAmountAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShortTermDebtLineItems" xlink:to="DebtLongtermAndShorttermCombinedAmountAbstract" xlink:title="definition: ShortTermDebtLineItems to DebtLongtermAndShorttermCombinedAmountAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowings" xlink:label="ShortTermBorrowings" xlink:title="ShortTermBorrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShortTermDebtLineItems" xlink:to="ShortTermBorrowings" xlink:title="definition: ShortTermDebtLineItems to ShortTermBorrowings" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="LineOfCreditFacilityMaximumBorrowingCapacity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShortTermDebtLineItems" xlink:to="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="definition: ShortTermDebtLineItems to LineOfCreditFacilityMaximumBorrowingCapacity" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod" xlink:label="LineOfCreditFacilityInterestRateDuringPeriod" xlink:title="LineOfCreditFacilityInterestRateDuringPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShortTermDebtLineItems" xlink:to="LineOfCreditFacilityInterestRateDuringPeriod" xlink:title="definition: ShortTermDebtLineItems to LineOfCreditFacilityInterestRateDuringPeriod" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="DebtInstrumentMaturityDate" xlink:title="DebtInstrumentMaturityDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShortTermDebtLineItems" xlink:to="DebtInstrumentMaturityDate" xlink:title="definition: ShortTermDebtLineItems to DebtInstrumentMaturityDate" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="ScheduleOfShortTermDebtTable" xlink:title="ScheduleOfShortTermDebtTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShortTermDebtLineItems" xlink:to="ScheduleOfShortTermDebtTable" xlink:title="definition: ShortTermDebtLineItems to ScheduleOfShortTermDebtTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShortTermDebtTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: ScheduleOfShortTermDebtTable to DebtInstrumentAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain_2" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain_2" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit1Member" xlink:label="LineOfCredit1Member" xlink:title="LineOfCredit1Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit1Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit1Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit2Member" xlink:label="LineOfCredit2Member" xlink:title="LineOfCredit2Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit2Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit2Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit3Member" xlink:label="LineOfCredit3Member" xlink:title="LineOfCredit3Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit3Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit3Member" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit4Member" xlink:label="LineOfCredit4Member" xlink:title="LineOfCredit4Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit4Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit4Member" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit5Member" xlink:label="LineOfCredit5Member" xlink:title="LineOfCredit5Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit5Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit5Member" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit6Member" xlink:label="LineOfCredit6Member" xlink:title="LineOfCredit6Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit6Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit6Member" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit7Member" xlink:label="LineOfCredit7Member" xlink:title="LineOfCredit7Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit7Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit7Member" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit8Member" xlink:label="LineOfCredit8Member" xlink:title="LineOfCredit8Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit8Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit8Member" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit9Member" xlink:label="LineOfCredit9Member" xlink:title="LineOfCredit9Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit9Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit9Member" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit10Member" xlink:label="LineOfCredit10Member" xlink:title="LineOfCredit10Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit10Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit10Member" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit11Member" xlink:label="LineOfCredit11Member" xlink:title="LineOfCredit11Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit11Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit11Member" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit12Member" xlink:label="LineOfCredit12Member" xlink:title="LineOfCredit12Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit12Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit12Member" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit13Member" xlink:label="LineOfCredit13Member" xlink:title="LineOfCredit13Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit13Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit13Member" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit14Member" xlink:label="LineOfCredit14Member" xlink:title="LineOfCredit14Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit14Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit14Member" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit15Member" xlink:label="LineOfCredit15Member" xlink:title="LineOfCredit15Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit15Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit15Member" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit16Member" xlink:label="LineOfCredit16Member" xlink:title="LineOfCredit16Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit16Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit16Member" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit17Member" xlink:label="LineOfCredit17Member" xlink:title="LineOfCredit17Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit17Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit17Member" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit18Member" xlink:label="LineOfCredit18Member" xlink:title="LineOfCredit18Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit18Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit18Member" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit19Member" xlink:label="LineOfCredit19Member" xlink:title="LineOfCredit19Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit19Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit19Member" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit20Member" xlink:label="LineOfCredit20Member" xlink:title="LineOfCredit20Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit20Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit20Member" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit25Member" xlink:label="LineOfCredit25Member" xlink:title="LineOfCredit25Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit25Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit25Member" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit28Member" xlink:label="LineOfCredit28Member" xlink:title="LineOfCredit28Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit28Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit28Member" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LineOfCredit29Member" xlink:label="LineOfCredit29Member" xlink:title="LineOfCredit29Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCredit29Member" xlink:title="definition: DebtInstrumentNameDomain to LineOfCredit29Member" order="23.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherPayableAndAccruedExpensesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LeasesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LeasesDetailsCalc01" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LongtermBorrowingsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="LineOfCreditFacilityLineItems" xlink:title="LineOfCreditFacilityLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtCurrentAndNoncurrentAbstract" xlink:label="LongtermDebtCurrentAndNoncurrentAbstract" xlink:title="LongtermDebtCurrentAndNoncurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongtermDebtCurrentAndNoncurrentAbstract" xlink:title="definition: LineOfCreditFacilityLineItems to LongtermDebtCurrentAndNoncurrentAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_DebtInstrumentsNumberOfLoans" xlink:label="DebtInstrumentsNumberOfLoans" xlink:title="DebtInstrumentsNumberOfLoans" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="DebtInstrumentsNumberOfLoans" xlink:title="definition: LineOfCreditFacilityLineItems to DebtInstrumentsNumberOfLoans" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NumberOfInstallmentsForLoanRepayable" xlink:label="NumberOfInstallmentsForLoanRepayable" xlink:title="NumberOfInstallmentsForLoanRepayable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="NumberOfInstallmentsForLoanRepayable" xlink:title="definition: LineOfCreditFacilityLineItems to NumberOfInstallmentsForLoanRepayable" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="DebtInstrumentMaturityDate" xlink:title="DebtInstrumentMaturityDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="DebtInstrumentMaturityDate" xlink:title="definition: LineOfCreditFacilityLineItems to DebtInstrumentMaturityDate" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod" xlink:label="LineOfCreditFacilityInterestRateDuringPeriod" xlink:title="LineOfCreditFacilityInterestRateDuringPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LineOfCreditFacilityInterestRateDuringPeriod" xlink:title="definition: LineOfCreditFacilityLineItems to LineOfCreditFacilityInterestRateDuringPeriod" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtByMaturityAbstract" xlink:label="LongTermDebtByMaturityAbstract" xlink:title="LongTermDebtByMaturityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtByMaturityAbstract" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtByMaturityAbstract" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsIncurred" xlink:label="InterestCostsIncurred" xlink:title="InterestCostsIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="InterestCostsIncurred" xlink:title="definition: LineOfCreditFacilityLineItems to InterestCostsIncurred" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseLongTermDebt" xlink:label="InterestExpenseLongTermDebt" xlink:title="InterestExpenseLongTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="InterestExpenseLongTermDebt" xlink:title="definition: LineOfCreditFacilityLineItems to InterestExpenseLongTermDebt" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsCapitalized" xlink:label="InterestCostsCapitalized" xlink:title="InterestCostsCapitalized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="InterestCostsCapitalized" xlink:title="definition: LineOfCreditFacilityLineItems to InterestCostsCapitalized" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LongTermDebtMaturitiesRepaymentsOfPrincipalYearFiveAndAfter" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalYearFiveAndAfter" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalYearFiveAndAfter" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalYearFiveAndAfter" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalYearFiveAndAfter" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt" xlink:label="LongTermDebt" xlink:title="LongTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebt" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebt" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="LongTermDebtCurrent" xlink:title="LongTermDebtCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtCurrent" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtCurrent" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="LongTermDebtNoncurrent" xlink:title="LongTermDebtNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LongTermDebtNoncurrent" xlink:title="definition: LineOfCreditFacilityLineItems to LongTermDebtNoncurrent" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="LineOfCreditFacilityTable" xlink:title="LineOfCreditFacilityTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="LineOfCreditFacilityLineItems" xlink:to="LineOfCreditFacilityTable" xlink:title="definition: LineOfCreditFacilityLineItems to LineOfCreditFacilityTable" order="18.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="LineOfCreditFacilityAxis" xlink:title="LineOfCreditFacilityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LineOfCreditFacilityTable" xlink:to="LineOfCreditFacilityAxis" xlink:title="definition: LineOfCreditFacilityTable to LineOfCreditFacilityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="LineOfCreditFacilityLenderDomain" xlink:title="LineOfCreditFacilityLenderDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LineOfCreditFacilityAxis" xlink:to="LineOfCreditFacilityLenderDomain" xlink:title="definition: LineOfCreditFacilityAxis to LineOfCreditFacilityLenderDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="LineOfCreditFacilityLenderDomain_2" xlink:title="LineOfCreditFacilityLenderDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LineOfCreditFacilityAxis" xlink:to="LineOfCreditFacilityLenderDomain_2" xlink:title="definition: LineOfCreditFacilityAxis to LineOfCreditFacilityLenderDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ChinaMerchantsBankMember" xlink:label="ChinaMerchantsBankMember" xlink:title="ChinaMerchantsBankMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLenderDomain" xlink:to="ChinaMerchantsBankMember" xlink:title="definition: LineOfCreditFacilityLenderDomain to ChinaMerchantsBankMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_BankOfChinaMember" xlink:label="BankOfChinaMember" xlink:title="BankOfChinaMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LineOfCreditFacilityLenderDomain" xlink:to="BankOfChinaMember" xlink:title="definition: LineOfCreditFacilityLenderDomain to BankOfChinaMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LineOfCreditFacilityTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: LineOfCreditFacilityTable to DebtInstrumentAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain_2" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain_2" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LoanOneMember" xlink:label="LoanOneMember" xlink:title="LoanOneMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LoanOneMember" xlink:title="definition: DebtInstrumentNameDomain to LoanOneMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LoanTwoMember" xlink:label="LoanTwoMember" xlink:title="LoanTwoMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LoanTwoMember" xlink:title="definition: DebtInstrumentNameDomain to LoanTwoMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LongtermBorrowingsDetailsCalc2" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/OtherLongtermLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrentAbstract" xlink:label="OtherLiabilitiesNoncurrentAbstract" xlink:title="OtherLiabilitiesNoncurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="OtherLiabilitiesNoncurrentAbstract" xlink:title="definition: DebtInstrumentLineItems to OtherLiabilitiesNoncurrentAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="OtherLiabilitiesNoncurrent" xlink:title="OtherLiabilitiesNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="OtherLiabilitiesNoncurrent" xlink:title="definition: DebtInstrumentLineItems to OtherLiabilitiesNoncurrent" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: DebtInstrumentTable to DebtInstrumentAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain_2" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain_2" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiesToStressFreePolishingProjectMember" xlink:label="SubsidiesToStressFreePolishingProjectMember" xlink:title="SubsidiesToStressFreePolishingProjectMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="SubsidiesToStressFreePolishingProjectMember" xlink:title="definition: DebtInstrumentNameDomain to SubsidiesToStressFreePolishingProjectMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiesToElectroCopperPlatingProjectMember" xlink:label="SubsidiesToElectroCopperPlatingProjectMember" xlink:title="SubsidiesToElectroCopperPlatingProjectMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="SubsidiesToElectroCopperPlatingProjectMember" xlink:title="definition: DebtInstrumentNameDomain to SubsidiesToElectroCopperPlatingProjectMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiesToPolytetrafluoroethyleneMember" xlink:label="SubsidiesToPolytetrafluoroethyleneMember" xlink:title="SubsidiesToPolytetrafluoroethyleneMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="SubsidiesToPolytetrafluoroethyleneMember" xlink:title="definition: DebtInstrumentNameDomain to SubsidiesToPolytetrafluoroethyleneMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiesToTahoeSingleBenchCleanCommencedIn2020Member" xlink:label="SubsidiesToTahoeSingleBenchCleanCommencedIn2020Member" xlink:title="SubsidiesToTahoeSingleBenchCleanCommencedIn2020Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="SubsidiesToTahoeSingleBenchCleanCommencedIn2020Member" xlink:title="definition: DebtInstrumentNameDomain to SubsidiesToTahoeSingleBenchCleanCommencedIn2020Member" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiesToOtherCleaningToolsCommencedIn2020Member" xlink:label="SubsidiesToOtherCleaningToolsCommencedIn2020Member" xlink:title="SubsidiesToOtherCleaningToolsCommencedIn2020Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="SubsidiesToOtherCleaningToolsCommencedIn2020Member" xlink:title="definition: DebtInstrumentNameDomain to SubsidiesToOtherCleaningToolsCommencedIn2020Member" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SubsidiesToSWLingangRDDevelopmentIn2021Member" xlink:label="SubsidiesToSWLingangRDDevelopmentIn2021Member" xlink:title="SubsidiesToSWLingangRDDevelopmentIn2021Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="SubsidiesToSWLingangRDDevelopmentIn2021Member" xlink:title="definition: DebtInstrumentNameDomain to SubsidiesToSWLingangRDDevelopmentIn2021Member" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_OtherMember" xlink:label="OtherMember" xlink:title="OtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="OtherMember" xlink:title="definition: DebtInstrumentNameDomain to OtherMember" order="7.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/LongtermInvestmentDetails">
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LongTermInvestmentLineItems" xlink:label="LongTermInvestmentLineItems" xlink:title="LongTermInvestmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentsAbstract" xlink:label="InvestmentsAbstract" xlink:title="InvestmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="InvestmentsAbstract" xlink:title="definition: LongTermInvestmentLineItems to InvestmentsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="EquityMethodInvestmentOwnershipPercentage" xlink:title="EquityMethodInvestmentOwnershipPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="EquityMethodInvestmentOwnershipPercentage" xlink:title="definition: LongTermInvestmentLineItems to EquityMethodInvestmentOwnershipPercentage" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentAggregateCost" xlink:label="EquityMethodInvestmentAggregateCost" xlink:title="EquityMethodInvestmentAggregateCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="EquityMethodInvestmentAggregateCost" xlink:title="definition: LongTermInvestmentLineItems to EquityMethodInvestmentAggregateCost" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesIssued" xlink:label="SharesIssued" xlink:title="SharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="SharesIssued" xlink:title="definition: LongTermInvestmentLineItems to SharesIssued" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesIssuedPricePerShare" xlink:label="SharesIssuedPricePerShare" xlink:title="SharesIssuedPricePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="SharesIssuedPricePerShare" xlink:title="definition: LongTermInvestmentLineItems to SharesIssuedPricePerShare" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="EquityMethodInvestments" xlink:title="EquityMethodInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="EquityMethodInvestments" xlink:title="definition: LongTermInvestmentLineItems to EquityMethodInvestments" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NumberOfInvestorsWithAgreementsEntered" xlink:label="NumberOfInvestorsWithAgreementsEntered" xlink:title="NumberOfInvestorsWithAgreementsEntered" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="NumberOfInvestorsWithAgreementsEntered" xlink:title="definition: LongTermInvestmentLineItems to NumberOfInvestorsWithAgreementsEntered" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_InvestmentInPartnership" xlink:label="InvestmentInPartnership" xlink:title="InvestmentInPartnership" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="InvestmentInPartnership" xlink:title="definition: LongTermInvestmentLineItems to InvestmentInPartnership" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_OwnershipPercentageInPartnership" xlink:label="OwnershipPercentageInPartnership" xlink:title="OwnershipPercentageInPartnership" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="OwnershipPercentageInPartnership" xlink:title="definition: LongTermInvestmentLineItems to OwnershipPercentageInPartnership" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ClassificationOfInvestmentsAbstract" xlink:label="ClassificationOfInvestmentsAbstract" xlink:title="ClassificationOfInvestmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="ClassificationOfInvestmentsAbstract" xlink:title="definition: LongTermInvestmentLineItems to ClassificationOfInvestmentsAbstract" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromEquityMethodInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="IncomeLossFromEquityMethodInvestments" xlink:title="definition: LongTermInvestmentLineItems to IncomeLossFromEquityMethodInvestments" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:label="ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:title="ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:title="definition: LongTermInvestmentLineItems to ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Investments" xlink:label="Investments" xlink:title="Investments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermInvestmentLineItems" xlink:to="Investments" xlink:title="definition: LongTermInvestmentLineItems to Investments" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_LongTermInvestmentTable" xlink:label="LongTermInvestmentTable" xlink:title="LongTermInvestmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="LongTermInvestmentLineItems" xlink:to="LongTermInvestmentTable" xlink:title="definition: LongTermInvestmentLineItems to LongTermInvestmentTable" order="14.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="InvestmentTypeAxis" xlink:title="InvestmentTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LongTermInvestmentTable" xlink:to="InvestmentTypeAxis" xlink:title="definition: LongTermInvestmentTable to InvestmentTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="InvestmentTypeCategorizationMember" xlink:title="InvestmentTypeCategorizationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="InvestmentTypeAxis" xlink:to="InvestmentTypeCategorizationMember" xlink:title="definition: InvestmentTypeAxis to InvestmentTypeCategorizationMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="InvestmentTypeCategorizationMember_2" xlink:title="InvestmentTypeCategorizationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="InvestmentTypeAxis" xlink:to="InvestmentTypeCategorizationMember_2" xlink:title="definition: InvestmentTypeAxis to InvestmentTypeCategorizationMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLongTermInvestmentsMember" xlink:label="OtherLongTermInvestmentsMember" xlink:title="OtherLongTermInvestmentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InvestmentTypeCategorizationMember" xlink:to="OtherLongTermInvestmentsMember" xlink:title="definition: InvestmentTypeCategorizationMember to OtherLongTermInvestmentsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_InvestmentExcludingOtherMember" xlink:label="InvestmentExcludingOtherMember" xlink:title="InvestmentExcludingOtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InvestmentTypeCategorizationMember" xlink:to="InvestmentExcludingOtherMember" xlink:title="definition: InvestmentTypeCategorizationMember to InvestmentExcludingOtherMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LongTermInvestmentTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: LongTermInvestmentTable to RelatedPartyTransactionsByRelatedPartyAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NinebellCompanyLimitedMember" xlink:label="NinebellCompanyLimitedMember" xlink:title="NinebellCompanyLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="NinebellCompanyLimitedMember" xlink:title="definition: RelatedPartyDomain to NinebellCompanyLimitedMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShengyiSemiconductorTechnologyCompanyLimitedMember" xlink:label="ShengyiSemiconductorTechnologyCompanyLimitedMember" xlink:title="ShengyiSemiconductorTechnologyCompanyLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="ShengyiSemiconductorTechnologyCompanyLimitedMember" xlink:title="definition: RelatedPartyDomain to ShengyiSemiconductorTechnologyCompanyLimitedMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_HefeiShixiChanhengIntegratedCircuitIndustryVentureCapitalFundPartnershipMember" xlink:label="HefeiShixiChanhengIntegratedCircuitIndustryVentureCapitalFundPartnershipMember" xlink:title="HefeiShixiChanhengIntegratedCircuitIndustryVentureCapitalFundPartnershipMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="HefeiShixiChanhengIntegratedCircuitIndustryVentureCapitalFundPartnershipMember" xlink:title="definition: RelatedPartyDomain to HefeiShixiChanhengIntegratedCircuitIndustryVentureCapitalFundPartnershipMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_WaferworksCompanyLimitedMember" xlink:label="WaferworksCompanyLimitedMember" xlink:title="WaferworksCompanyLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="WaferworksCompanyLimitedMember" xlink:title="definition: RelatedPartyDomain to WaferworksCompanyLimitedMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LongTermInvestmentTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: LongTermInvestmentTable to StatementClassOfStockAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/FinancialLiabilityCarriedAtFairValueDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="RelatedPartyTransactionLineItems" xlink:title="RelatedPartyTransactionLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" xlink:label="RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" xlink:title="RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" xlink:title="definition: RelatedPartyTransactionLineItems to RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CashDeliveredAsOfCloseOfBusiness" xlink:label="CashDeliveredAsOfCloseOfBusiness" xlink:title="CashDeliveredAsOfCloseOfBusiness" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="CashDeliveredAsOfCloseOfBusiness" xlink:title="definition: RelatedPartyTransactionLineItems to CashDeliveredAsOfCloseOfBusiness" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="StockIssuedDuringPeriodSharesNewIssues" xlink:title="StockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="StockIssuedDuringPeriodSharesNewIssues" xlink:title="definition: RelatedPartyTransactionLineItems to StockIssuedDuringPeriodSharesNewIssues" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="StockIssuedDuringPeriodValueNewIssues" xlink:title="StockIssuedDuringPeriodValueNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="StockIssuedDuringPeriodValueNewIssues" xlink:title="definition: RelatedPartyTransactionLineItems to StockIssuedDuringPeriodValueNewIssues" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_InvestmentRepaymentPeriod" xlink:label="InvestmentRepaymentPeriod" xlink:title="InvestmentRepaymentPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="InvestmentRepaymentPeriod" xlink:title="definition: RelatedPartyTransactionLineItems to InvestmentRepaymentPeriod" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:label="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:title="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:title="definition: RelatedPartyTransactionLineItems to StockIssuedDuringPeriodSharesCommonStockWarrantExercised" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="DebtInstrumentFaceAmount" xlink:title="DebtInstrumentFaceAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DebtInstrumentFaceAmount" xlink:title="definition: RelatedPartyTransactionLineItems to DebtInstrumentFaceAmount" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="DebtInstrumentInterestRateStatedPercentage" xlink:title="DebtInstrumentInterestRateStatedPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DebtInstrumentInterestRateStatedPercentage" xlink:title="definition: RelatedPartyTransactionLineItems to DebtInstrumentInterestRateStatedPercentage" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="DebtInstrumentMaturityDate" xlink:title="DebtInstrumentMaturityDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DebtInstrumentMaturityDate" xlink:title="definition: RelatedPartyTransactionLineItems to DebtInstrumentMaturityDate" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="StockRepurchasedDuringPeriodShares" xlink:title="StockRepurchasedDuringPeriodShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="StockRepurchasedDuringPeriodShares" xlink:title="definition: RelatedPartyTransactionLineItems to StockRepurchasedDuringPeriodShares" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentOfNotesReceivableFromRelatedParties" xlink:label="RepaymentOfNotesReceivableFromRelatedParties" xlink:title="RepaymentOfNotesReceivableFromRelatedParties" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RepaymentOfNotesReceivableFromRelatedParties" xlink:title="definition: RelatedPartyTransactionLineItems to RepaymentOfNotesReceivableFromRelatedParties" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NumberOfAgreements" xlink:label="NumberOfAgreements" xlink:title="NumberOfAgreements" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="NumberOfAgreements" xlink:title="definition: RelatedPartyTransactionLineItems to NumberOfAgreements" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsForProceedsFromInvestments" xlink:label="PaymentsForProceedsFromInvestments" xlink:title="PaymentsForProceedsFromInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="PaymentsForProceedsFromInvestments" xlink:title="definition: RelatedPartyTransactionLineItems to PaymentsForProceedsFromInvestments" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:label="DueToRelatedPartiesCurrentAndNoncurrent" xlink:title="DueToRelatedPartiesCurrentAndNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DueToRelatedPartiesCurrentAndNoncurrent" xlink:title="definition: RelatedPartyTransactionLineItems to DueToRelatedPartiesCurrentAndNoncurrent" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="ReceivablesNetCurrent" xlink:title="ReceivablesNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ReceivablesNetCurrent" xlink:title="definition: RelatedPartyTransactionLineItems to ReceivablesNetCurrent" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ConsiderationPriceInFairValue" xlink:label="ConsiderationPriceInFairValue" xlink:title="ConsiderationPriceInFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ConsiderationPriceInFairValue" xlink:title="definition: RelatedPartyTransactionLineItems to ConsiderationPriceInFairValue" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialLiabilitiesFairValueDisclosure" xlink:label="FinancialLiabilitiesFairValueDisclosure" xlink:title="FinancialLiabilitiesFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="FinancialLiabilitiesFairValueDisclosure" xlink:title="definition: RelatedPartyTransactionLineItems to FinancialLiabilitiesFairValueDisclosure" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" xlink:label="IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" xlink:title="IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" xlink:title="definition: RelatedPartyTransactionLineItems to IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IssuanceOfWarrantForSettlementOfFinancialLiability" xlink:label="IssuanceOfWarrantForSettlementOfFinancialLiability" xlink:title="IssuanceOfWarrantForSettlementOfFinancialLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="IssuanceOfWarrantForSettlementOfFinancialLiability" xlink:title="definition: RelatedPartyTransactionLineItems to IssuanceOfWarrantForSettlementOfFinancialLiability" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WarrantsNotSettleableInCashFairValueDisclosure" xlink:label="WarrantsNotSettleableInCashFairValueDisclosure" xlink:title="WarrantsNotSettleableInCashFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="WarrantsNotSettleableInCashFairValueDisclosure" xlink:title="definition: RelatedPartyTransactionLineItems to WarrantsNotSettleableInCashFairValueDisclosure" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="definition: RelatedPartyTransactionLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharePrice" xlink:label="SharePrice" xlink:title="SharePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="SharePrice" xlink:title="definition: RelatedPartyTransactionLineItems to SharePrice" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="definition: RelatedPartyTransactionLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="definition: RelatedPartyTransactionLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="definition: RelatedPartyTransactionLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="definition: RelatedPartyTransactionLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="definition: RelatedPartyTransactionLineItems to ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" order="27.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" xlink:label="ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" xlink:title="ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" xlink:title="definition: RelatedPartyDomain to ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to ConsolidatedEntitiesAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SubsidiariesMember" xlink:label="SubsidiariesMember" xlink:title="SubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="SubsidiariesMember" xlink:title="definition: ConsolidatedEntitiesDomain to SubsidiariesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchShanghaiIncMember" xlink:label="ACMResearchShanghaiIncMember" xlink:title="ACMResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchShanghaiIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to StatementClassOfStockAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="LongtermDebtTypeAxis" xlink:title="LongtermDebtTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="LongtermDebtTypeAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to LongtermDebtTypeAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain_2" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain_2" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="SeniorNotesMember" xlink:title="SeniorNotesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="SeniorNotesMember" xlink:title="definition: LongtermDebtTypeDomain to SeniorNotesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IntercompanyNoteMember" xlink:label="IntercompanyNoteMember" xlink:title="IntercompanyNoteMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="IntercompanyNoteMember" xlink:title="definition: LongtermDebtTypeDomain to IntercompanyNoteMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="BalanceSheetLocationAxis" xlink:title="BalanceSheetLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="BalanceSheetLocationAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to BalanceSheetLocationAxis" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="BalanceSheetLocationDomain" xlink:title="BalanceSheetLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BalanceSheetLocationAxis" xlink:to="BalanceSheetLocationDomain" xlink:title="definition: BalanceSheetLocationAxis to BalanceSheetLocationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="BalanceSheetLocationDomain_2" xlink:title="BalanceSheetLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BalanceSheetLocationAxis" xlink:to="BalanceSheetLocationDomain_2" xlink:title="definition: BalanceSheetLocationAxis to BalanceSheetLocationDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_OtherReceivablesCurrentMember" xlink:label="OtherReceivablesCurrentMember" xlink:title="OtherReceivablesCurrentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BalanceSheetLocationDomain" xlink:to="OtherReceivablesCurrentMember" xlink:title="definition: BalanceSheetLocationDomain to OtherReceivablesCurrentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="ClassOfWarrantOrRightAxis" xlink:title="ClassOfWarrantOrRightAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="ClassOfWarrantOrRightAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to ClassOfWarrantOrRightAxis" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain_2" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain_2" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" xlink:label="ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" xlink:title="ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/TradingSecuritiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:label="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:title="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentsAbstract" xlink:label="InvestmentsAbstract" xlink:title="InvestmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="InvestmentsAbstract" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to InvestmentsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_TradingSecuritiesListedInShanghaiStockExchangeAbstract" xlink:label="TradingSecuritiesListedInShanghaiStockExchangeAbstract" xlink:title="TradingSecuritiesListedInShanghaiStockExchangeAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="TradingSecuritiesListedInShanghaiStockExchangeAbstract" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to TradingSecuritiesListedInShanghaiStockExchangeAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesTradingUnrealizedGain" xlink:label="DebtSecuritiesTradingUnrealizedGain" xlink:title="DebtSecuritiesTradingUnrealizedGain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="DebtSecuritiesTradingUnrealizedGain" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to DebtSecuritiesTradingUnrealizedGain" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TradingSecuritiesDebtAmortizedCost" xlink:label="TradingSecuritiesDebtAmortizedCost" xlink:title="TradingSecuritiesDebtAmortizedCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="TradingSecuritiesDebtAmortizedCost" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to TradingSecuritiesDebtAmortizedCost" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_DebtSecuritiesTradingSecuritiesEquity" xlink:label="DebtSecuritiesTradingSecuritiesEquity" xlink:title="DebtSecuritiesTradingSecuritiesEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="DebtSecuritiesTradingSecuritiesEquity" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to DebtSecuritiesTradingSecuritiesEquity" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CapitalFundOfLimitedPartnership" xlink:label="CapitalFundOfLimitedPartnership" xlink:title="CapitalFundOfLimitedPartnership" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="CapitalFundOfLimitedPartnership" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to CapitalFundOfLimitedPartnership" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_InvestmentInPartnership" xlink:label="InvestmentInPartnership" xlink:title="InvestmentInPartnership" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="InvestmentInPartnership" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to InvestmentInPartnership" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_OwnershipPercentageInPartnership" xlink:label="OwnershipPercentageInPartnership" xlink:title="OwnershipPercentageInPartnership" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="OwnershipPercentageInPartnership" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to OwnershipPercentageInPartnership" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:label="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:title="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" order="9.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable to RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_QingdaoFortuneTechXinxingCapitalPartnershipMember" xlink:label="QingdaoFortuneTechXinxingCapitalPartnershipMember" xlink:title="QingdaoFortuneTechXinxingCapitalPartnershipMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="QingdaoFortuneTechXinxingCapitalPartnershipMember" xlink:title="definition: RelatedPartyDomain to QingdaoFortuneTechXinxingCapitalPartnershipMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_SemiconductorManufacturingInternationalCorporationMember" xlink:label="SemiconductorManufacturingInternationalCorporationMember" xlink:title="SemiconductorManufacturingInternationalCorporationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="SemiconductorManufacturingInternationalCorporationMember" xlink:title="definition: RelatedPartyDomain to SemiconductorManufacturingInternationalCorporationMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RelatedPartyBalancesAndTransactionsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="RelatedPartyTransactionLineItems" xlink:title="RelatedPartyTransactionLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" xlink:label="RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" xlink:title="RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" xlink:title="definition: RelatedPartyTransactionLineItems to RelatedPartyTransactionDueFromToRelatedPartyCurrentAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_RelatedPartyTransactionPrepaidExpenseFromRelatedParty" xlink:label="RelatedPartyTransactionPrepaidExpenseFromRelatedParty" xlink:title="RelatedPartyTransactionPrepaidExpenseFromRelatedParty" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RelatedPartyTransactionPrepaidExpenseFromRelatedParty" xlink:title="definition: RelatedPartyTransactionLineItems to RelatedPartyTransactionPrepaidExpenseFromRelatedParty" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="AccountsPayableRelatedPartiesCurrent" xlink:title="AccountsPayableRelatedPartiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="AccountsPayableRelatedPartiesCurrent" xlink:title="definition: RelatedPartyTransactionLineItems to AccountsPayableRelatedPartiesCurrent" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionPurchasesFromRelatedParty" xlink:label="RelatedPartyTransactionPurchasesFromRelatedParty" xlink:title="RelatedPartyTransactionPurchasesFromRelatedParty" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RelatedPartyTransactionPurchasesFromRelatedParty" xlink:title="definition: RelatedPartyTransactionLineItems to RelatedPartyTransactionPurchasesFromRelatedParty" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyCosts" xlink:label="RelatedPartyCosts" xlink:title="RelatedPartyCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RelatedPartyCosts" xlink:title="definition: RelatedPartyTransactionLineItems to RelatedPartyCosts" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="definition: RelatedPartyTransactionLineItems to ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_NinebellCoLtdMember" xlink:label="NinebellCoLtdMember" xlink:title="NinebellCoLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="NinebellCoLtdMember" xlink:title="definition: RelatedPartyDomain to NinebellCoLtdMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShanghaiZhangjiangGroupCoLtdMember" xlink:label="ShanghaiZhangjiangGroupCoLtdMember" xlink:title="ShanghaiZhangjiangGroupCoLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="ShanghaiZhangjiangGroupCoLtdMember" xlink:title="definition: RelatedPartyDomain to ShanghaiZhangjiangGroupCoLtdMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/CommonStockDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="ClassOfStockLineItems" xlink:title="ClassOfStockLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDisclosuresAbstract" xlink:label="ClassOfStockDisclosuresAbstract" xlink:title="ClassOfStockDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="ClassOfStockDisclosuresAbstract" xlink:title="definition: ClassOfStockLineItems to ClassOfStockDisclosuresAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="CommonStockSharesAuthorized" xlink:title="CommonStockSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonStockSharesAuthorized" xlink:title="definition: ClassOfStockLineItems to CommonStockSharesAuthorized" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_AdditionalSharesReservedForIssuanceAsDividends" xlink:label="AdditionalSharesReservedForIssuanceAsDividends" xlink:title="AdditionalSharesReservedForIssuanceAsDividends" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="AdditionalSharesReservedForIssuanceAsDividends" xlink:title="definition: ClassOfStockLineItems to AdditionalSharesReservedForIssuanceAsDividends" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_CommonStockAdditionalSharesAuthorized" xlink:label="CommonStockAdditionalSharesAuthorized" xlink:title="CommonStockAdditionalSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonStockAdditionalSharesAuthorized" xlink:title="definition: ClassOfStockLineItems to CommonStockAdditionalSharesAuthorized" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="CommonStockParOrStatedValuePerShare" xlink:title="CommonStockParOrStatedValuePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonStockParOrStatedValuePerShare" xlink:title="definition: ClassOfStockLineItems to CommonStockParOrStatedValuePerShare" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_VotingRightsPerShare" xlink:label="VotingRightsPerShare" xlink:title="VotingRightsPerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="VotingRightsPerShare" xlink:title="definition: ClassOfStockLineItems to VotingRightsPerShare" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConversionOfStockSharesConverted1" xlink:label="ConversionOfStockSharesConverted1" xlink:title="ConversionOfStockSharesConverted1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="ConversionOfStockSharesConverted1" xlink:title="definition: ClassOfStockLineItems to ConversionOfStockSharesConverted1" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:label="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:title="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" xlink:title="definition: ClassOfStockLineItems to StockIssuedDuringPeriodSharesCommonStockWarrantExercised" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: ClassOfStockLineItems to StockIssuedDuringPeriodSharesStockOptionsExercised" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="StockIssuedDuringPeriodSharesNewIssues" xlink:title="StockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockIssuedDuringPeriodSharesNewIssues" xlink:title="definition: ClassOfStockLineItems to StockIssuedDuringPeriodSharesNewIssues" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharePrice" xlink:label="SharePrice" xlink:title="SharePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="SharePrice" xlink:title="definition: ClassOfStockLineItems to SharePrice" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="ProceedsFromIssuanceOfCommonStock" xlink:title="ProceedsFromIssuanceOfCommonStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="ProceedsFromIssuanceOfCommonStock" xlink:title="definition: ClassOfStockLineItems to ProceedsFromIssuanceOfCommonStock" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_UnderwritingDiscountAndOfferingExpenses" xlink:label="UnderwritingDiscountAndOfferingExpenses" xlink:title="UnderwritingDiscountAndOfferingExpenses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="UnderwritingDiscountAndOfferingExpenses" xlink:title="definition: ClassOfStockLineItems to UnderwritingDiscountAndOfferingExpenses" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="StockRepurchasedDuringPeriodShares" xlink:title="StockRepurchasedDuringPeriodShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockRepurchasedDuringPeriodShares" xlink:title="definition: ClassOfStockLineItems to StockRepurchasedDuringPeriodShares" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:label="StockIssuedDuringPeriodSharesConversionOfUnits" xlink:title="StockIssuedDuringPeriodSharesConversionOfUnits" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockIssuedDuringPeriodSharesConversionOfUnits" xlink:title="definition: ClassOfStockLineItems to StockIssuedDuringPeriodSharesConversionOfUnits" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="CommonStockSharesIssued" xlink:title="CommonStockSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonStockSharesIssued" xlink:title="definition: ClassOfStockLineItems to CommonStockSharesIssued" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="CommonStockSharesOutstanding" xlink:title="CommonStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonStockSharesOutstanding" xlink:title="definition: ClassOfStockLineItems to CommonStockSharesOutstanding" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="ScheduleOfStockByClassTable" xlink:title="ScheduleOfStockByClassTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ClassOfStockLineItems" xlink:to="ScheduleOfStockByClassTable" xlink:title="definition: ClassOfStockLineItems to ScheduleOfStockByClassTable" order="18.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: ScheduleOfStockByClassTable to StatementEquityComponentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="CommonStockMember" xlink:title="definition: EquityComponentDomain to CommonStockMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: ScheduleOfStockByClassTable to StatementClassOfStockAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassAMember" xlink:title="definition: ClassOfStockDomain to CommonClassAMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="CommonClassBMember" xlink:title="CommonClassBMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonClassBMember" xlink:title="definition: ClassOfStockDomain to CommonClassBMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: ScheduleOfStockByClassTable to RelatedPartyTransactionsByRelatedPartyAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" xlink:label="ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" xlink:title="ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" xlink:title="definition: RelatedPartyDomain to ShengxinShanghaiManagementConsultingLimitedPartnershipSMCMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="ClassOfWarrantOrRightAxis" xlink:title="ClassOfWarrantOrRightAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="ClassOfWarrantOrRightAxis" xlink:title="definition: ScheduleOfStockByClassTable to ClassOfWarrantOrRightAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain_2" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain_2" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" xlink:label="ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" xlink:title="ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to ShengxinShanghaiManagementConsultingLimitedPartnership2020WarrantsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RedeemableNoncontrollingInterestsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/StockbasedCompensationStockbasedCompensationExpenseDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:title="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationAbstract" xlink:label="ShareBasedCompensationAbstract" xlink:title="ShareBasedCompensationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="ShareBasedCompensationAbstract" xlink:title="definition: EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems to ShareBasedCompensationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="AllocatedShareBasedCompensationExpense" xlink:title="AllocatedShareBasedCompensationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="AllocatedShareBasedCompensationExpense" xlink:title="definition: EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems to AllocatedShareBasedCompensationExpense" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:title="ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:title="definition: EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems to ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="IncomeStatementLocationAxis" xlink:title="IncomeStatementLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="IncomeStatementLocationAxis" xlink:title="definition: ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable to IncomeStatementLocationAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="IncomeStatementLocationDomain" xlink:title="IncomeStatementLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeStatementLocationAxis" xlink:to="IncomeStatementLocationDomain" xlink:title="definition: IncomeStatementLocationAxis to IncomeStatementLocationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="IncomeStatementLocationDomain_2" xlink:title="IncomeStatementLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeStatementLocationAxis" xlink:to="IncomeStatementLocationDomain_2" xlink:title="definition: IncomeStatementLocationAxis to IncomeStatementLocationDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="CostOfSalesMember" xlink:title="CostOfSalesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementLocationDomain" xlink:to="CostOfSalesMember" xlink:title="definition: IncomeStatementLocationDomain to CostOfSalesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="SellingAndMarketingExpenseMember" xlink:title="SellingAndMarketingExpenseMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementLocationDomain" xlink:to="SellingAndMarketingExpenseMember" xlink:title="definition: IncomeStatementLocationDomain to SellingAndMarketingExpenseMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="ResearchAndDevelopmentExpenseMember" xlink:title="ResearchAndDevelopmentExpenseMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementLocationDomain" xlink:to="ResearchAndDevelopmentExpenseMember" xlink:title="definition: IncomeStatementLocationDomain to ResearchAndDevelopmentExpenseMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="GeneralAndAdministrativeExpenseMember" xlink:title="GeneralAndAdministrativeExpenseMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementLocationDomain" xlink:to="GeneralAndAdministrativeExpenseMember" xlink:title="definition: IncomeStatementLocationDomain to GeneralAndAdministrativeExpenseMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable to AwardTypeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:label="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:title="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to ShareBasedPaymentArrangementNonEmployeeStockOptionMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable to ConsolidatedEntitiesAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SubsidiariesMember" xlink:label="SubsidiariesMember" xlink:title="SubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="SubsidiariesMember" xlink:title="definition: ConsolidatedEntitiesDomain to SubsidiariesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchShanghaiIncMember" xlink:label="ACMResearchShanghaiIncMember" xlink:title="ACMResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchShanghaiIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/StockbasedCompensationAssumptionsUsedToDetermineFairValueOfShareOptionsGrantedDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharePrice" xlink:label="SharePrice" xlink:title="SharePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharePrice" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="PlanNameAxis" xlink:title="PlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="PlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to PlanNameAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain" xlink:title="definition: PlanNameAxis to PlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain_2" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain_2" xlink:title="definition: PlanNameAxis to PlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ServicePeriodBasedApproachMember" xlink:label="ServicePeriodBasedApproachMember" xlink:title="ServicePeriodBasedApproachMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="ServicePeriodBasedApproachMember" xlink:title="definition: PlanNameDomain to ServicePeriodBasedApproachMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_MarketBasedMember" xlink:label="MarketBasedMember" xlink:title="MarketBasedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="MarketBasedMember" xlink:title="definition: PlanNameDomain to MarketBasedMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to RangeAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/StockbasedCompensationShareOptionActivitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="AllocatedShareBasedCompensationExpense" xlink:title="AllocatedShareBasedCompensationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="AllocatedShareBasedCompensationExpense" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to AllocatedShareBasedCompensationExpense" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodWeightedAverageGrantDateFairValue" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpiredInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpiredInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpiredInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpiredInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpiredInPeriodWeightedAverageGrantDateFairValue" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedWeightedAverageGrantDateFairValue" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedWeightedAverageGrantDateFairValue" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedWeightedAverageGrantDateFairValue" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to StockIssuedDuringPeriodSharesStockOptionsExercised" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="25.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:label="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:title="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="ShareBasedPaymentArrangementNonEmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to ShareBasedPaymentArrangementNonEmployeeStockOptionMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to ConsolidatedEntitiesAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SubsidiariesMember" xlink:label="SubsidiariesMember" xlink:title="SubsidiariesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="SubsidiariesMember" xlink:title="definition: ConsolidatedEntitiesDomain to SubsidiariesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ACMResearchShanghaiIncMember" xlink:label="ACMResearchShanghaiIncMember" xlink:title="ACMResearchShanghaiIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsidiariesMember" xlink:to="ACMResearchShanghaiIncMember" xlink:title="definition: SubsidiariesMember to ACMResearchShanghaiIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/IncomeTaxesDetails">
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IncomeTaxesLineItems" xlink:label="IncomeTaxesLineItems" xlink:title="IncomeTaxesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="definition: IncomeTaxesLineItems to ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:label="ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:title="ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:title="definition: IncomeTaxesLineItems to ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="IncomeTaxExpenseBenefitContinuingOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxExpenseBenefitContinuingOperationsAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:label="EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:title="EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:label="ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:title="ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:title="definition: IncomeTaxesLineItems to ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" xlink:label="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" xlink:title="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:label="UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:title="UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="UnrecognizedTaxBenefits" xlink:title="UnrecognizedTaxBenefits" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefits" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefits" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:label="UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:title="UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:label="UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:title="UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:label="UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:title="UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:label="UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:title="UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:title="EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:label="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:title="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:label="EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:title="EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:label="EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:title="EffectiveIncomeTaxRateReconciliationOtherAdjustments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateReconciliationOtherAdjustments" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:label="EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:title="EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" xlink:label="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" xlink:title="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:label="EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:title="EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="EffectiveIncomeTaxRateContinuingOperations" xlink:title="EffectiveIncomeTaxRateContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectiveIncomeTaxRateContinuingOperations" xlink:title="definition: IncomeTaxesLineItems to EffectiveIncomeTaxRateContinuingOperations" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="ValuationAllowanceDeferredTaxAssetChangeInAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="definition: IncomeTaxesLineItems to ValuationAllowanceDeferredTaxAssetChangeInAmount" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="OperatingLossCarryforwards" xlink:title="OperatingLossCarryforwards" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="OperatingLossCarryforwards" xlink:title="definition: IncomeTaxesLineItems to OperatingLossCarryforwards" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwardsExpirationDate" xlink:label="OperatingLossCarryforwardsExpirationDate" xlink:title="OperatingLossCarryforwardsExpirationDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="OperatingLossCarryforwardsExpirationDate" xlink:title="definition: IncomeTaxesLineItems to OperatingLossCarryforwardsExpirationDate" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" xlink:label="DeferredTaxAssetsTaxCreditCarryforwardsResearch" xlink:title="DeferredTaxAssetsTaxCreditCarryforwardsResearch" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsTaxCreditCarryforwardsResearch" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsTaxCreditCarryforwardsResearch" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxCreditCarryforwardExpirationDate" xlink:label="TaxCreditCarryforwardExpirationDate" xlink:title="TaxCreditCarryforwardExpirationDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="TaxCreditCarryforwardExpirationDate" xlink:title="definition: IncomeTaxesLineItems to TaxCreditCarryforwardExpirationDate" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_OperatingLossCarryforwardsSubjectToAnnualLimitationOwnershipChange" xlink:label="OperatingLossCarryforwardsSubjectToAnnualLimitationOwnershipChange" xlink:title="OperatingLossCarryforwardsSubjectToAnnualLimitationOwnershipChange" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="OperatingLossCarryforwardsSubjectToAnnualLimitationOwnershipChange" xlink:title="definition: IncomeTaxesLineItems to OperatingLossCarryforwardsSubjectToAnnualLimitationOwnershipChange" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_ForeignCorporateTaxRate" xlink:label="ForeignCorporateTaxRate" xlink:title="ForeignCorporateTaxRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="ForeignCorporateTaxRate" xlink:title="definition: IncomeTaxesLineItems to ForeignCorporateTaxRate" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_EffectivePeriodOfPreferentialIncomeTaxRate" xlink:label="EffectivePeriodOfPreferentialIncomeTaxRate" xlink:title="EffectivePeriodOfPreferentialIncomeTaxRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="EffectivePeriodOfPreferentialIncomeTaxRate" xlink:title="definition: IncomeTaxesLineItems to EffectivePeriodOfPreferentialIncomeTaxRate" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsNetAbstract" xlink:label="DeferredTaxAssetsNetAbstract" xlink:title="DeferredTaxAssetsNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsNetAbstract" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsNetAbstract" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:label="DeferredTaxLiabilitiesNetAbstract" xlink:title="DeferredTaxLiabilitiesNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxLiabilitiesNetAbstract" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxLiabilitiesNetAbstract" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_DeferredTaxAssetsLiabilitiesTranslationDifference" xlink:label="DeferredTaxAssetsLiabilitiesTranslationDifference" xlink:title="DeferredTaxAssetsLiabilitiesTranslationDifference" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsLiabilitiesTranslationDifference" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsLiabilitiesTranslationDifference" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="DeferredTaxAssetsLiabilitiesNet" xlink:title="DeferredTaxAssetsLiabilitiesNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsLiabilitiesNet" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsLiabilitiesNet" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOtherFiniteLivedAssets" xlink:label="DeferredTaxLiabilitiesOtherFiniteLivedAssets" xlink:title="DeferredTaxLiabilitiesOtherFiniteLivedAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxLiabilitiesOtherFiniteLivedAssets" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxLiabilitiesOtherFiniteLivedAssets" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome" xlink:label="DeferredTaxLiabilitiesTaxDeferredIncome" xlink:title="DeferredTaxLiabilitiesTaxDeferredIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxLiabilitiesTaxDeferredIncome" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxLiabilitiesTaxDeferredIncome" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities" xlink:label="DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities" xlink:title="DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_DeferredTaxLiabilitiesEquityInvestments" xlink:label="DeferredTaxLiabilitiesEquityInvestments" xlink:title="DeferredTaxLiabilitiesEquityInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxLiabilitiesEquityInvestments" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxLiabilitiesEquityInvestments" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilities" xlink:label="DeferredTaxLiabilities" xlink:title="DeferredTaxLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxLiabilities" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxLiabilities" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign" xlink:label="DeferredTaxAssetsOperatingLossCarryforwardsForeign" xlink:title="DeferredTaxAssetsOperatingLossCarryforwardsForeign" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsOperatingLossCarryforwardsForeign" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsOperatingLossCarryforwardsForeign" order="38.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic" xlink:label="DeferredTaxAssetsOperatingLossCarryforwardsDomestic" xlink:title="DeferredTaxAssetsOperatingLossCarryforwardsDomestic" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsOperatingLossCarryforwardsDomestic" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsOperatingLossCarryforwardsDomestic" order="39.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsDeferredIncome" xlink:label="DeferredTaxAssetsDeferredIncome" xlink:title="DeferredTaxAssetsDeferredIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsDeferredIncome" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsDeferredIncome" order="40.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts" xlink:label="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts" xlink:title="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts" order="41.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" xlink:label="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" xlink:title="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" order="42.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:label="DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:title="DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" order="43.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment" xlink:label="DeferredTaxAssetsPropertyPlantAndEquipment" xlink:title="DeferredTaxAssetsPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsPropertyPlantAndEquipment" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsPropertyPlantAndEquipment" order="44.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_DeferredTaxAssetsLeaseLiability" xlink:label="DeferredTaxAssetsLeaseLiability" xlink:title="DeferredTaxAssetsLeaseLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsLeaseLiability" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsLeaseLiability" order="45.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="DeferredTaxAssetsGross" xlink:title="DeferredTaxAssetsGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsGross" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsGross" order="46.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="DeferredTaxAssetsValuationAllowance" xlink:title="DeferredTaxAssetsValuationAllowance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsValuationAllowance" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsValuationAllowance" order="47.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="DeferredTaxAssetsNet" xlink:title="DeferredTaxAssetsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsNet" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsNet" order="48.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="definition: IncomeTaxesLineItems to CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" order="49.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="definition: IncomeTaxesLineItems to DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" order="50.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxExpenseBenefit" order="51.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:label="DeferredFederalIncomeTaxExpenseBenefit" xlink:title="DeferredFederalIncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredFederalIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to DeferredFederalIncomeTaxExpenseBenefit" order="52.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:label="DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:title="DeferredStateAndLocalIncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to DeferredStateAndLocalIncomeTaxExpenseBenefit" order="53.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:label="DeferredForeignIncomeTaxExpenseBenefit" xlink:title="DeferredForeignIncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredForeignIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to DeferredForeignIncomeTaxExpenseBenefit" order="54.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefit" xlink:label="DeferredFederalStateAndLocalTaxExpenseBenefit" xlink:title="DeferredFederalStateAndLocalTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredFederalStateAndLocalTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to DeferredFederalStateAndLocalTaxExpenseBenefit" order="55.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:label="CurrentFederalTaxExpenseBenefit" xlink:title="CurrentFederalTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="CurrentFederalTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to CurrentFederalTaxExpenseBenefit" order="56.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="CurrentStateAndLocalTaxExpenseBenefit" xlink:title="CurrentStateAndLocalTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="CurrentStateAndLocalTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to CurrentStateAndLocalTaxExpenseBenefit" order="57.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentForeignTaxExpenseBenefit" xlink:label="CurrentForeignTaxExpenseBenefit" xlink:title="CurrentForeignTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="CurrentForeignTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to CurrentForeignTaxExpenseBenefit" order="58.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:label="CurrentIncomeTaxExpenseBenefit" xlink:title="CurrentIncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="CurrentIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to CurrentIncomeTaxExpenseBenefit" order="59.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IncomeTaxesTable" xlink:label="IncomeTaxesTable" xlink:title="IncomeTaxesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxesTable" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxesTable" order="60.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="IncomeTaxAuthorityAxis" xlink:title="IncomeTaxAuthorityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeTaxesTable" xlink:to="IncomeTaxAuthorityAxis" xlink:title="definition: IncomeTaxesTable to IncomeTaxAuthorityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="IncomeTaxAuthorityDomain" xlink:title="IncomeTaxAuthorityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeTaxAuthorityAxis" xlink:to="IncomeTaxAuthorityDomain" xlink:title="definition: IncomeTaxAuthorityAxis to IncomeTaxAuthorityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="IncomeTaxAuthorityDomain_2" xlink:title="IncomeTaxAuthorityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeTaxAuthorityAxis" xlink:to="IncomeTaxAuthorityDomain_2" xlink:title="definition: IncomeTaxAuthorityAxis to IncomeTaxAuthorityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DomesticCountryMember" xlink:label="DomesticCountryMember" xlink:title="DomesticCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="DomesticCountryMember" xlink:title="definition: IncomeTaxAuthorityDomain to DomesticCountryMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="StateAndLocalJurisdictionMember" xlink:title="StateAndLocalJurisdictionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="StateAndLocalJurisdictionMember" xlink:title="definition: IncomeTaxAuthorityDomain to StateAndLocalJurisdictionMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="ForeignCountryMember" xlink:title="ForeignCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="ForeignCountryMember" xlink:title="definition: IncomeTaxAuthorityDomain to ForeignCountryMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeTaxesTable" xlink:to="RangeAxis" xlink:title="definition: IncomeTaxesTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/SegmentInformationDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/CommitmentsAndContingenciesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/RestrictedNetAssetsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationCondensedBalanceSheetDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:label="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:title="CondensedBalanceSheetStatementsCaptionsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="AssetsAbstract" xlink:title="AssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="AssetsAbstract" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to AssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="LiabilitiesAndStockholdersEquityAbstract" xlink:title="LiabilitiesAndStockholdersEquityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="LiabilitiesAndStockholdersEquityAbstract" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to LiabilitiesAndStockholdersEquityAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableAndOtherAccruedLiabilities" xlink:label="AccountsPayableAndOtherAccruedLiabilities" xlink:title="AccountsPayableAndOtherAccruedLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="AccountsPayableAndOtherAccruedLiabilities" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to AccountsPayableAndOtherAccruedLiabilities" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNotesPayable" xlink:label="OtherNotesPayable" xlink:title="OtherNotesPayable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="OtherNotesPayable" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to OtherNotesPayable" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedIncomeTaxesCurrent" xlink:label="AccruedIncomeTaxesCurrent" xlink:title="AccruedIncomeTaxesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="AccruedIncomeTaxesCurrent" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to AccruedIncomeTaxesCurrent" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" xlink:label="IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" xlink:title="IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to IncomeTaxesCurrentPayableAndDeferredTaxLiabilities" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="DeferredIncomeTaxLiabilitiesNet" xlink:title="DeferredIncomeTaxLiabilitiesNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="DeferredIncomeTaxLiabilitiesNet" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to DeferredIncomeTaxLiabilitiesNet" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Liabilities" xlink:label="Liabilities" xlink:title="Liabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="Liabilities" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to Liabilities" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="StockholdersEquity" xlink:title="StockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="StockholdersEquity" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to StockholdersEquity" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="LiabilitiesAndStockholdersEquity" xlink:title="LiabilitiesAndStockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="LiabilitiesAndStockholdersEquity" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to LiabilitiesAndStockholdersEquity" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="AssetsCurrentAbstract" xlink:title="AssetsCurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="AssetsCurrentAbstract" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to AssetsCurrentAbstract" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:title="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets" xlink:label="Assets" xlink:title="Assets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="Assets" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to Assets" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="CashAndCashEquivalentsAtCarryingValue" xlink:title="CashAndCashEquivalentsAtCarryingValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="CashAndCashEquivalentsAtCarryingValue" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to CashAndCashEquivalentsAtCarryingValue" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="AccountsReceivableNetCurrent" xlink:title="AccountsReceivableNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="AccountsReceivableNetCurrent" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to AccountsReceivableNetCurrent" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueFromAffiliateCurrent" xlink:label="DueFromAffiliateCurrent" xlink:title="DueFromAffiliateCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="DueFromAffiliateCurrent" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to DueFromAffiliateCurrent" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherReceivablesNetCurrent" xlink:label="OtherReceivablesNetCurrent" xlink:title="OtherReceivablesNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="OtherReceivablesNetCurrent" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to OtherReceivablesNetCurrent" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="PrepaidExpenseCurrent" xlink:title="PrepaidExpenseCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="PrepaidExpenseCurrent" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to PrepaidExpenseCurrent" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="AssetsCurrent" xlink:title="AssetsCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="AssetsCurrent" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to AssetsCurrent" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="DeferredIncomeTaxAssetsNet" xlink:title="DeferredIncomeTaxAssetsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="DeferredIncomeTaxAssetsNet" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to DeferredIncomeTaxAssetsNet" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedBalanceSheetStatementTable" xlink:label="CondensedBalanceSheetStatementTable" xlink:title="CondensedBalanceSheetStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="CondensedBalanceSheetStatementsCaptionsLineItems" xlink:to="CondensedBalanceSheetStatementTable" xlink:title="definition: CondensedBalanceSheetStatementsCaptionsLineItems to CondensedBalanceSheetStatementTable" order="21.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="CondensedBalanceSheetStatementTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: CondensedBalanceSheetStatementTable to ConsolidatedEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ParentCompanyMember" xlink:label="ParentCompanyMember" xlink:title="ParentCompanyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="ParentCompanyMember" xlink:title="definition: ConsolidatedEntitiesDomain to ParentCompanyMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationCondensedStatementOfOperationsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedIncomeStatementsCaptionsLineItems" xlink:label="CondensedIncomeStatementsCaptionsLineItems" xlink:title="CondensedIncomeStatementsCaptionsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="IncomeStatementAbstract" xlink:title="IncomeStatementAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="IncomeStatementAbstract" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to IncomeStatementAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to RevenueFromContractWithCustomerExcludingAssessedTax" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="CostOfRevenue" xlink:title="CostOfRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="CostOfRevenue" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to CostOfRevenue" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GrossProfit" xlink:label="GrossProfit" xlink:title="GrossProfit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="GrossProfit" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to GrossProfit" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="OperatingExpensesAbstract" xlink:title="OperatingExpensesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="OperatingExpensesAbstract" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to OperatingExpensesAbstract" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="OperatingIncomeLoss" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to OperatingIncomeLoss" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromEquityMethodInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="IncomeLossFromEquityMethodInvestments" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to IncomeLossFromEquityMethodInvestments" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="acmr-20211231.xsd#acmr_IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" xlink:label="IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" xlink:title="IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to IncreaseDecreaseInFinancialLiabilityCarriedAtFairValue" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="InvestmentIncomeInterest" xlink:title="InvestmentIncomeInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="InvestmentIncomeInterest" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to InvestmentIncomeInterest" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense" xlink:label="InterestExpense" xlink:title="InterestExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="InterestExpense" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to InterestExpense" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="NonoperatingIncomeExpense" xlink:title="NonoperatingIncomeExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="NonoperatingIncomeExpense" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to NonoperatingIncomeExpense" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to IncomeTaxExpenseBenefit" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="NetIncomeLoss" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to NetIncomeLoss" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="SellingAndMarketingExpense" xlink:title="SellingAndMarketingExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="SellingAndMarketingExpense" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to SellingAndMarketingExpense" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="GeneralAndAdministrativeExpense" xlink:title="GeneralAndAdministrativeExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="GeneralAndAdministrativeExpense" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to GeneralAndAdministrativeExpense" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="ResearchAndDevelopmentExpense" xlink:title="ResearchAndDevelopmentExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="ResearchAndDevelopmentExpense" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to ResearchAndDevelopmentExpense" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedIncomeStatementTable" xlink:label="CondensedIncomeStatementTable" xlink:title="CondensedIncomeStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="CondensedIncomeStatementsCaptionsLineItems" xlink:to="CondensedIncomeStatementTable" xlink:title="definition: CondensedIncomeStatementsCaptionsLineItems to CondensedIncomeStatementTable" order="18.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="CondensedIncomeStatementTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: CondensedIncomeStatementTable to ConsolidatedEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ParentCompanyMember" xlink:label="ParentCompanyMember" xlink:title="ParentCompanyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="ParentCompanyMember" xlink:title="definition: ConsolidatedEntitiesDomain to ParentCompanyMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://acmrcsh.com/role/ParentCompanyOnlyCondensedFinancialInformationCondensedStatementOfCashFlowsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:label="CondensedCashFlowStatementsCaptionsLineItems" xlink:title="CondensedCashFlowStatementsCaptionsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="StatementOfCashFlowsAbstract" xlink:title="StatementOfCashFlowsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="StatementOfCashFlowsAbstract" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to StatementOfCashFlowsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="NetCashProvidedByUsedInOperatingActivities" xlink:title="NetCashProvidedByUsedInOperatingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="NetCashProvidedByUsedInOperatingActivities" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to NetCashProvidedByUsedInOperatingActivities" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="NetCashProvidedByUsedInInvestingActivities" xlink:title="NetCashProvidedByUsedInInvestingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="NetCashProvidedByUsedInInvestingActivities" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to NetCashProvidedByUsedInInvestingActivities" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="NetCashProvidedByUsedInFinancingActivities" xlink:title="NetCashProvidedByUsedInFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="NetCashProvidedByUsedInFinancingActivities" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to NetCashProvidedByUsedInFinancingActivities" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:title="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:title="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:title="EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedCashFlowStatementTable" xlink:label="CondensedCashFlowStatementTable" xlink:title="CondensedCashFlowStatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="CondensedCashFlowStatementsCaptionsLineItems" xlink:to="CondensedCashFlowStatementTable" xlink:title="definition: CondensedCashFlowStatementsCaptionsLineItems to CondensedCashFlowStatementTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="CondensedCashFlowStatementTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: CondensedCashFlowStatementTable to ConsolidatedEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ParentCompanyMember" xlink:label="ParentCompanyMember" xlink:title="ParentCompanyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="ParentCompanyMember" xlink:title="definition: ConsolidatedEntitiesDomain to ParentCompanyMember" order="1.0" />
  </link:definitionLink>
</link:linkbase>
