Thespatialimpulseresponse(SIR)methodisoftenusedasthe’goldstandard5insimulationoftransientacousticwavefieldsduetoitshighaccuracyinthelineardomain.However,ahighsamplingfrequencyisoftenrequiredinordertoachievethehighaccuracy.Asaresult,alargeamountofdatahastobeprocessed.Inthispaperafastapproachforcomputingspatialimpulseresponseisproposedtoreducethecomputationburden.TheproposedapproachisdevelopedbyemployingtherelationshipofSIRsatobservedpointsandSIRsoftheprojectionpointsonthetransducersurface.Twocriticalparametersusedintheproposedapproach,thecalculationsamplingfrequencyandtheinterpolationsamplingfrequency,arethenanalyzed.Resultsshowthatfora2.25MHzrectangulartransducerwiththesizeof5mmxlOmm,acalculationsamplingfrequencyof1000MHzandaninterpolationsamplingfrequencyof500MHzcanachievesuperiorperformancewhileimprovingthecomputationefficiency18timesthanthedirectsolving.