There is insufficient research on the deformation laws and construction measures of the underpass high-speed railway station project. This article takes the Tianjin Metro Line 4 North Section Undercrossing Tianjin West Station project as the background, and uses large-scale finite element software to conduct numerical simulation of the undercrossing project, verifying the effectiveness of various construction measures, and analyzing the deformation of the pile foundation. Research has shown that the filling and grouting construction of the gaps around the shield and the secondary grouting construction have a good effect on reducing ground settlement; Thickening the bottom plate can reduce the vertical deformation of the shield tunneling structure to a certain extent, and the frame structure of the station building itself reduces the impact of shield tunneling to a certain extent; The greater the pressure on the palm face, the greater the lateral displacement of the upper part of the pile foundation away from the shield tunneling, and the greater the displacement towards the direction of the shield tunneling; The greater the grouting pressure, the smaller the lateral and longitudinal deformation of the pile foundation; During the process of shield tunneling, the top of the pile foundation is constantly sinking, while the bottom is slightly raised. The research results can provide reference and reference for similar projects such as shield tunneling through existing underground structures.