Based on transversely isotropic and ideal elastic-plastic models, numerical simulation and analysis of different excavation types (circular, gated, four-center and flat-bottomed horseshoe) for diversion tunnel are carried out using FLAC3D software. It is concluded that the circular excavation section is the optimal section, and based on the circular excavation section with the diameter of 16 m, it is obtained that the tunnel group will not lose stability in the case of local instability of adjacent tunnels. The allowable limit safe distance of adjacent tunnel excavation is 45 m, and finally, the measured results are obtained by selecting 600 m,800 m,1000 m,1200 m depth to simulate the hole exploration. The circular section with a diameter of 16 m is excavated in the upper and lower half of the face, which is the evolution law of the large rate of deformation and failure of surrounding rock when the tunnel is pushed to one time the distance of the tunnel, which is the excavation stage of the key protection of excavation and can be used as a reference for the later construction.