Simplified mechanical model can not reflect the real situation of the interaction between foundation and cables. Then numerical software FLAC3D is used to simulate the procedure of foundation excavation and cable reinforcement. Deformation responses of foundation are analyzed as well as the mechanical response of cables. The results show that, (1) the procedure of excavation leads to the deformation of soil mass in foundation, which is the reasons of tensile failure and shear failure; for tensile failure areas, the length of soil nailing should be set surpass the slip plane; for shear failure areas, the density of cables should be set larger at the place of shear opening. (2) after excavation, the axial stress distributes different along the cable shaft, location of maximum axial stress along cable can indicate the location of potential slip plane. FLAC3D can simulate the excavation and reinforcement of foundation reasonably, whose result can give guidance for design and construction.