Abstract: The rigid pile composite foundation consists of the raft, the piles, the foundation soil and the cushion between the raft and the piles. Research on the rigid pile composite foundation is at present still inadequate, and the knowledge on its working mechanism is quite limited. In this paper, the working performance of rigid pile composite foundation is analyzed by using the finite element method. Factors influencing axial stress of piles and settlements of rigid pile composite foundation under vertical load are studied. The influence factors include cushion thickness, cushion modulus, pile length, soil modulus, pile spacing, etc. The design principles of composite foundation are proposed.