Based on the construction of the shield tunnel of the southwest ring road in Taiyuan railway hub, combined with the monitoring data in shield construction, the finite element analysis software is used to carry out numerical simulation analysis. Considering the fluid-structure coupling, combined with the actual monitoring data, the stability of the surface and underground structure when the shield passes through the viaduct is studied, and the deformation laws of the surface, bridge caps and bridge piles and the distribution laws of pore water pressure around the tunnel are obtained. The results show that: It is necessary and reasonable to consider the fluid-solid coupling effect in the shield tunnel crossing viaduct project in water-rich strata. Before shield tunnel construction, the reinforcement measures of isolation pile combined with deep stratum grouting can effectively control the deformation of ground surface, bridge caps and bridge piles. In the process of shield tunneling, it mainly affects the horizontal lateral displacement of bridge piles, but has little influence on the horizontal longitudinal and vertical displacement. The additional bending moment on the top of the bridge pile is larger. Grouting reinforcement measures in deep strata can weaken the fluid-solid coupling around the tunnel and reduce the risk of water gushing in the tunnel.