Today routesimulationplays animportant roleforshipownersand operatorstochecktheperformanceofshipsailingunderenvironmentaldisturbancesuchaswind,waveandcurrent.Inaddition,seawaveshaveagreatinfluenceontheship’sstructureaswellastheseakeepingperformanceofaship.Itisveryimportanttoestimatethecorrectinducedwaveforceforanalyzingseakeepingperformanceofaship.Inthepresentstudy,anumericalseakeepinganalysisofaKRISOcontainership(KCS)wasperformedinregularwavesinvariouswavedirections.ThehydrodynamicinteractionsbetweentheshipandtheregularwaveswereinvestigatedusingPanelMethod.ThenumericalseakeepinganalyseswereperformedinAQWAsoftware.KCSwasselectedinthisstudyandthenumericalanalysisofheaveandpitchinheadseaconditionhavebeencomparedwiththeexperimentalresult.TheresultoftheheaveandpitchmotionsofKCSinheadseaconditionsinthepresentstudyhavegoodagreementwiththeexperimentalresult.Theeffectofwavelengthoncharacterizingthemotionresponseofashipinvariouswavedirectionwasdiscussed.Particularly,thenumericalresultsinthisstudycanbeusefulforestimatingrelativemotionandrelativevelocityofashipfordeterminingtheoptimalrouteavoidingtheslamminganddeckwetness.