Abstract: The behavior of rigid pile composite foundation under horizontal load is analyzed by using elastoplastic finite element method. It is investigated that the effects of different design parameters on the horizontal forced behavior of the composite foundation, with which the distribution law of internal forces along pile subjected to horizontal load is also obtained. Calculations show that vertical load at proper level will enhance the horizontal load bearing capacity of composite foundation. Due to the effect of the cushion layer in the composite foundation, the horizontal load transferred to piles will be decreased and the pile will be safer.