In order to study the dynamic characteristics of pile foundation with liquefiable sandy soil under seismic loading, the four working conditions are studied including natural foundation, pile foundation with 3D, 3.5D, 4D (D is pile diameter) pile space by means of indoor shaking table model test. Initial effective stress, time history of excess pore water pressure and time history of settlement during vibration are determined, at the same time, the vertical bearing capacity of pile reinforced foundation after vibration is compared with the vertical bearing capacity before vibration. The test results show that the liquefaction of pile reinforced foundation lags behind the natural foundation and pile foundation with 3D~3.5D can more significantly improve liquefaction resistance; The vertical dynamic bearing capacity of pile foundation with 3D is hignest in the light of largest settlement during vibration; the vertical bearing capacity of pile foundation becomes larger after vibration. Based on the test，the pile-soil-structure dynamic interaction was understood deeply during liquefaction, which will be referenced during the optimal design of pile foundation in the future.