Modularinversearithmeticplaysanimportantroleinellipticcurvecryptography.BasedontheanalysisofMontgomerymodularinversionalgorithm,thispaperpresentsanewdual-fieldmodularinversionalgorithm,andanovelscalableandunifiedarchitectureforMontgomeryinversehardwareinfinitefieldsGF(p)andGF(2n)isproposed.Furthermore,thisarchitecturebasedonthenewmodularinversionalgorithmhasbeenverifiedbymodelingitinVerilog-HDL,andaccomplisheditunder0.18μmCMOStechnology.Theresultindicatesthatourworkhasbetterperformanceandflexibilitythanotherworks.