Abstract: The theoretical evaluation for the dynamic behavior of pile-soil-structure under horizontal seismic load was conducted based on the combination of plane dynamic FEM and simplified 3D concentrating-mass method(S-R model).The structural dynamic response with different types,number of pile-group and soil properties could be expediently educed.With a computation example,it was indicated that structural and interstorey displacement should augment considering the effect of interaction due to the participation of relative flexible soil-foundation,but internal structural forces under some seismic frequency-spectrum would increase owing to varied pile-soil-structure system properties.In addition,an acceleration response spectrum curves on condition of fix-base did not necessarily include that on condition of soil-pile-structure interaction.These two methods were consistenty for the quantitative numerical analysis and qualitative evaluation on responses of interaction structures.