［Purposes］ Excavating a tunnel crossing a water-bearing fault fracture zone results in significantly different stability of the surrounding rock compared to that in a non-fault area. This difference causes changes in the safety of the surrounding rock of the unlined tunnel and lining structure during construction and operation. ［Methods］ For further studying the deteriorating effect of seepage on the stability of surrounding rock, it is necessary to analyze the coupling effect between the seepage field of surrounding rock and the secondary stress field of tunnel surrounding rock excavation and point out the most unfavorable excavation position and stress location. ［Findings］ This paper takes the actual project of Xiangjiang Tunnel on Yingpan Road in Changsha City as an example and uses finite element software for simulation. The study analyzes the change characteristics of the seepage field, stress field, displacement field, and plastic zone of the surrounding rock during excavation and determines the location of the tunnel face that is prone to sudden water inrush disasters and the influence range of the fault. ［Conclusions］The research results indicate that the seepage discharge of the upper step is significantly higher than that of the middle and lower steps, and the maximum seepage discharge occurs on the left and right sides of the tunnel face. The displacement of the upper step is significantly greater than that of the middle and lower steps, and the maximum displacement occurs in the center of the tunnel face. The settlement of various parts in the fault zone is significantly greater than that in the normal surrounding rock zone, with the most obvious change being in the arch crown. A larger plastic zone of the surrounding rock is produced when the tunnel crosses the fault zone. When the tunnel face advances to about 10 m in front of the fault, the plastic zone in front of the tunnel face connects with the fault and extends to the surface. The degree of deterioration of surrounding rock at different locations by the fault varies. The strong influence zone includes the interior of the fault and 3 m before and after the fault, while the weak influence zone includes 20 m before and after the fault.