For　engineering　applications,　a　variety　of　simplified　analysis　models　and　calculation　methods　considering　the　hydrodynamic　force　have　been　proposed　based　on　the　assumption　of　incompressible　water.　Some　typical　methods　include　the　rigid-structure　method,　Morison　method　and　a　method　based　on　approximation　of　fundamental-frequency.　The　seismic　responses　of　elastic　cantilever　circular　piers　excited　by　horizontal　earthquake　were　analyzed　to　study　the　difference　caused　by　the　above　methods.　By　using　3　ground　motion　records　on　soft　soil　site　and　selecting　a　series　of　depth　and　wide-depth　ratio　as　parameters,　144　cases　of　bridge　piers　were　considered.　The　horizontal　displacement　at　the　top　of　the　piers,　shearing　force　and　bending　moment　at　the　bottom　were　compared　with　the　exact　solutions　based　on　the　radiation　theory　of　incompressible　water.　Then,　the　range,　mean　values　and　coefficient　of　variation　of　the　relative　errors　of　the　peak　values　of　responses　were　presented.　Based　on　the　analysis　of　errors,calculation　accuracy　of　the　simplified　methods　was　investigated　and　the　applicable　scope　was　given　preliminarily.　©　2019,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.