In order to analyze the effect of subsoil liquefaction on the seismic response of pile foundation, typical computation model in liquable ground was set up. Based on different constitutive models of the foundation soil before and after liquefaction and considering the nonlinear relation of pile-soil interaction, the dynamic finite difference analysis of group piles was carried out by using FLAC3D. The dynamic response characteristics of pile foundation considering liquefaction during earthquake are studied. Results show that the peak value of pore pressure ratio is different in different depth of the soil around pile, and the arriving time of the peak value of pore pressure ratio is later than that of the peak value of earthquake acceleration. At any time during the earthquake whether before or after the liquefaction the top moment of pile are larger than that of the pile shaft when the top pile is solidly embedded.