Jet grouting technology is widely employed as a reinforcement of excavation base in soft soil area. In this study, based on the monitoring data, numerical analysis of a railway station is carried out using PLAXIS 2D software. Firstly, comparison between the reinforced and unreinforced excavation cases is evaluated based on the analysis of deformation, bending moment of diaphragm wall and ground settlement. The results show that the lateral deformation of diaphragm wall and the ground settlement can be effectively reduced by basal grouting reinforcement in soft soil. Then four parameters, namely, the thickness of reinforcement zone, the penetration depth, the stiffness of diaphragm wall and the thickness of soft soil layer, are analyzed and discussed. The reasonable thickness of reinforcement zone and depth of diaphragm wall, and the sensitivity of deformation to the stiffness of diaphragm wall and the thickness of soft soil layer are also investigated.