Abstract: Based on the stress field calculated by the Mindlin stress theory with the pile diameter effect considered and the existing Mindlin homogenization stress summation method for calculating the settlement of pile group foundation, the deformation behavior of the pile group foundation as well as the homogenization effect of pile cap and the superstructure stiffness on the settlement deformation, the homogenized additional stress coefficient of foundation piles under the arbitrary pile distribution mode is proposed. In the light of the generalized model for specific shaft resistance distribution, the pile-pile homogenization stress coefficient table is given under different ratios of length to diameter and different pile spacing, so as to provide an effective simple method for the settlement of pile group foundation. The additional stress is provided for calculating the settlement of pile groups. This method is verified by the engineering examples. By comparing the Boussinesq method for deep foundation and the equivalent method, the calculated settlements are close to the measured ones at completion of settlement.