Abstract: Although currently nonlinear properties have been considered in some designs of the piled raft foundations,the superstructures are still not taken into account.It is meaningful to study the mechanism of the nonlinear interaction of the piled raft foundation and the superstructure and to optimize the design of piled raft foundations.In this paper,the sub-structure method is used to agglomerate the rigidity and load of the superstructure.The rafts is simulated by the plane-shell element,and the nonlinear performance of the piles is analyzed using the generalized shear displacement method,and the elastic interaction between the pile and the surrounding soils is determined by finite layer method.A new theoretical method and the corresponding computing program for the nonlinear analysis of the piled raft foundations with the consideration of their interactions with the superstructures are established.By the analysis to a real case,the nonlinear interaction mechanism and the reasonable layout of piles are further discussed.And finally the possible ways to optimize the design of the piles raft foundations are put forward in which the optimization object is the differential settlement.