In order to study the stability and deformation control of the surrounding rock when a very large cross-section deep-buried tunnel crosses a fault fracture zone, the Tongzi Tunnel was relied. Based on field measurement data, finite element software was used to analyze the deformation pattern of the surrounding rock as the long tunnel crossed the fault fracture zone. Furthermore, an orthogonal test was conducted on the geological characteristics of the fracture zone to perform a parameter sensitivity analysis. Additionally, in order to enhance the construction safety of the tunnel as it passes through the fault fracture zone, numerical simulation was employed to analyze the impact of deformation control on the surrounding rock with varying thicknesses of the reinforcement zone. The results reveal the following the surrounding rock within the fault zone is highly disturbed, with a slow convergence rate. The maximum settlement of the vault and the maximum convergence of the periphery occur in the middle of the fault zone, where deformation increases as the center of the fault zone is approached. The geological parameters of the fault fracture zone have differing impacts on the stability of the surrounding rocks. Specifically, their effects on the displacement of the tunnel arch and side wall are as follows: fault deterioration >fault width > fault dip > fault tendency, and fault dip > fault deterioration > fault width > fault tendency. Different slurry diffusion radii corresponds to varying effects on the displacement control of the surrounding rock within the fracture zone through the formation of the grouting reinforcement zone, optimally, the thickness of the reinforcement zone is determined to be 2 m.