In order to study the effect of skirt soil reinforcement on the deformation and stress of foundation pit, model tests were carried out for cases without bottom reinforcement and skirt reinforcement respectively. To realize the reinforcement of bottom soil, the method of reinforcing soil by pre-pouring in the process of filling was adopted. The ground subsidence,the lateral displacement of top beam,the bending moment of piles and the earth pressure are measured during excavation. Extensive FE parametric studies indicate that the skirt reinforcement can effectively reduce the lateral displacement of the supporting structure. Although surrounding settlements decreased, the effect is less obvious. The bending moment of the pile is slightly less than that of the pile without reinforcement. With the excavation, the earth pressure in the upper part of the pile decreases and pressure at the bottom increases as the pile rotates at a certain point under the pit. The depth of skirt reinforcement has greater influence on the deformation of foundation pit than the width of reinforcement. When the depth and width of soil reinforcement exceed a certain range, the effect of controlling the deformation of foundation pit is marginaly improved. The reinforcement depth should be 0.3~`0.4 times of the excavation depth and the width should be 0.35~0.45 times of the excavation depth.