In order to reduce the disturbance of foundation pit excavation on the stability of adjacent buildings, a numerical model was established using Abaqus for the support of foundation pit slopes. Factors such as stress distribution and regional deformation around the foundation pit were comprehensively considered, and the support effects of different soil nail wall support methods were compared and analyzed. Support parameters such as soil nail length and aperture were discussed. The results show that the stepped soil nail support method can effectively improve the overall strength of the slope soil, reduce the degree of stress concentration on the slope, and reduce the deformation of the slope soil. When using soil nails for slope support, the length of soil nail support parameters should be 7 m, the aperture should be 50 mm, and the layout should be stepped.