Abstract: The reflection and backscattering coefficients from BICSQS model,which is abbreviated from the Biot model with contact squirt flow and shear drag,and Biot-Stoll model Seafloors are calculated and compared by poroelastic interface scattering formula.In addition,the effect of bulk relaxation frequency and shear relaxation frequency on the coefficients of BICSQS model is analyzed.The results show that the reflection coefficients from the two models are visibly different at steep grazing angles and around the apparent critical angle,however the backscattering coefficients are visibly different only around the apparent critical angle,and the maximum values of difference are 1.5 dB and 2 dB, respectively;and that the coefficients from BICSQS model are slightly influenced by the bulk relaxation frequency and the shear relaxation frequency respectively at medium frequency ranges and higher frequency ranges.