The　thick　soft　superficial　layers　of　the　seabed　greatly　influence　ground　motion　generally.　It　is　worth　studying　how　to　find　out　the　influence　of　these　soft　layers　on　ground　motion　parameters　and　determine　reasonable　seismic　fortification　parameters　for　ocean　engineering.　Numerical　experiments　of　site　response　analysis　are　designed　using　two　offshore　engineering　sites　in　this　study.　First,　the　borehole　profiles　are　selected　and　stripped　layer　by　layer　to　generate　new　profiles.　Second,　108　acceleration　time　histories　are　synthesized　which　basically　represent　the　diversity　of　input　motions＇　amplitude　and　frequency.　Third,　a　method　that　can　automatically　calculate　characteristic　periods　and　normalize　response　spectra　is　created　to　improve　calculation　efficiency.　Fourth,　peak　accelerations,　response　spectra,　and　characteristic　periods　at　different　depths　of　the　profiles　with　different　stripping　depths　are　calculated.　The　results　show　that　the　thick　soft　superficial　layers　can　significantly　decrease　peak　ground　accelerations　and　increase　characteristic　periods,　resulting　in　serious　＂low-fat＂　response　spectra.　The　situation　can　be　greatly　improved　by　stripping　off　the　soft　superficial　layers.　After　stripping　off　the　thick　soft　superficial　silt　layers,　if　stripping　is　continued　further,　the　variation　in　the　superficial　amplification　ratios　of　peak　accelerations　and　superficial　characteristic　periods　will　no　longer　be　drastic,　and　the　superficial　amplification　ratios　and　characteristic　periods　both　tend　to　be　mostly　the　same.　The　relative　deviation　of　the　amplification　ratio　of　peak　ground　acceleration　between　a　profile　stripped　and　that　without　stripping　can　be　143%,　and　it　can　be　83%　for　characteristic　period.　It　is　advisable　to　strip　off　thick　soft　superficial　layers　to　perform　site　response　analysis,　and　the　shear　force　at　the　bottom　of　the　silt　should　be　considered　in　engineering　based　on　local　seismic　activity　level,　and　the　silt＇s　and　the　structure＇s　physical　parameters.