Abstract: In order to ensure the safety of the foundation pit excavation, we select the foundation pit engineering of a substation as the research object, based on the geotechnical engineering investigation report, the geological model based on the site drilling data and engineering geological section is established by means of geological modeling technology. The ABAQUS simulation software was used to simulate the foundation pit excavation. The Mohr-Coulomb elastoplastic constitutive model was used to calculate the nonlinear properties on the foundation. The discontinuous contact characteristics between the underground continuous wall and the soil were described by penalty function algorithm. By calculating the characteristics of soil deformation, surface settlement and foundation uplift in different excavation stages, combined with substation design requirements and site engineering geological conditions, it provides basis for foundation pit excavation construction. The results show that the amount of ground settlement behind the wall, the amount of basal uplift and the horizontal displacement of the soil behind the wall present a regular change with the process of excavation. Compared with the rough modeling, the model is built according to the results of engineering geological exploration, which can better reflect the actual situation of soil stability.