The indoor model test and the ABAQUS software numerical simulation method were used to study the effects of the reinforcement of the soil at the bottom of the pit on the deformation of the foundation pit, the force of the supporting structure and the change of the soil pressure behind the pile. The research shows that the full-frame reinforcement has the most obvious effect on reducing the bottom bulge of the foundation pit, and it is more obvious to reduce the lateral displacement of the supporting structure, and it is not obvious to reduce the surface settlement. The elastic modulus of the reinforced soil is obtained by the range analysis method. Increasing the reinforcement depth is more effective in restraining the lateral displacement of the retaining pile and the uplift of the pit. The variation of the lateral displacement of the retaining pile and the uplift of the pit bottom under the condition of six different cement mixing ratios and no soil reinforcement is explored. When the cement blending ratio exceeds a certain range, the reinforcement effect is not significantly improved. It is recommended that in the clay area with a water content of about 20%, the cement blending ratio is generally 5% to 20%; after the soil reinforcement depth exceeds a certain range The effect of controlling the deformation of the foundation pit is improved but not obvious. It is recommended that the depth of the soil reinforcement be 0.4 to 0.45 times the depth of the foundation pit.