Near-fault mountain tunnels often have serious site deformation and structural dislocation during the seismic damage process. In this paper, we establish a tunnel-envelope rock model including the fault fault zone and the surrounding complete enclosing rock body for a fault-traversed tunnel in western China, and carry out the numerical simulation of the dynamic force by applying the misaligned displacement of the uplift fault and the ground vibration loading. We analyse the overall slip condition of the rock body in the fracture zone during the uplift process of the upper plate, reveal the development and evolution law of the "funnel zone" of the backlash fault, put forward the influence interval of the fault movement on the tunnel, analyse the dynamic load response of the tunnel caused by strong seismic action under the condition of the fault's initial dislocation, reveal the coupling effect of the fault's initial dislocation and the seismic dynamic load, and summarize and summarize The distribution of internal force and deformation state of the tunnel is summarised, and the deformation and damage mode of the tunnel under the initial dislocation-strong earthquake coupling is revealed, so as to provide a theoretical basis for the seismic-resistant and fault-resistant design of tunnels through faults in high intensity zones.