A bridge is located in a complex area of engineering geological conditions. It is found that some pile foundations of the bridge have been uplifted to varying degrees, up to 309mm, which seriously affects the operation and driving safety of the bridge. Based on this, through theoretical analysis and Plaxis3D finite element software simulation, the cause mechanism of the bridge pile foundation arch is analyzed, and the influence of ground stress and goaf on the bridge pile foundation under different working conditions is studied. The results show that for the bridge in the valley area, the uplift of the bridge pile foundation caused by the equivalent ground stress is the largest, reaching about 300mm; the uplift of non-bridge area in goaf is greater than that of bridge pile foundation; it can be seen that the ground stress is the main reason for the arching of the bridge pile foundation.