Abstract: The reamed precast concrete (RPC) pile is composed of core precast concrete (PC) pile and peripheral reamed material condensate, and its load transfer behaviors are very complex due to the cooperative bearing mechanism of the core pile, reamed material and surrounding soil. To investigate the load transfer behaviors of the whole reamed precast concrete pile under bearing of the core pile, an elastic-failure model is adopted to characterize the interaction performance of the core pile-reamed body interface, and an ideal elastic-plastic model is used to simulate the nonlinear interaction between reamed body and soil interface. Considering the shear characteristics of the inner and outer interfaces and their coupling effects, a load transfer model is established for the RPC pile under bearing of the core pile, and the computational method is further provided. The applicability of the proposed method is examined by comparing the results with those of the field tests, and the load transfer behaviors of the RPC pile is discussed. The results indicate that the peripheral reamed body can effectively transfer the core pile load to the surrounding soil. Increasing the thickness and stiffness of the reamed body can improve the bearing performance of the composite pile. However, thicker reamed body may also restrict the play of the bearing capacity of the core pile. Increasing the stiffness of the reamed body is conducive to the joint action of the core pile and peripheral reamed body. In engineering design and practice, the interaction between core pile, reamed body and surrounding soil can be coordinated by adjusting the thickness and performance of the reamed body.