Abstract: The internal force of foundation on soft soils should be gotten by considering upper structure-foundation-soil interaction. The contact pressure and foundation deformation should be in accordance with the measured data, and they should be tested and verified through experiments and engineering practices. Based on the first analysis results, the iterative calculation should be considered. When the deviation of the contact pressure between the input subgrade stiffness and the initial subgrade stiffness is less than 10%, the calculated results of the foundation can meet the requirements of engineering safety.