Abstract: For the deep foundation pit of Laopupian Commercial and Residential Building, the whole process of its excavation is simulated and analyzed by use of the finite element software PLAXIS. The situations of stress and deformation of supporting structures of foundation pit and surrounding environment under complex conditions are studied. The numerical analysis and monitoring results show that the deformations of supporting structure system of the foundation pit and the surrounding environment can meet the requirements of the specifications for deformation control. It proves that PLAXIS HS model can effectively simulate and analyze the deformation of the surrounding environment influenced by excavation of the foundation pit, and the semi-inverse method used in this project can effectively control the deformation of the surrounding environment influenced by excavation of the foundation pit under complex conditions.