The unfavorable geological section with low strength and large deformation of the surrounding rock was selected as the representative section for the calculation and analysis, and the FLAC3D model was used to study the deformation and stress of surrounding rock of tunnel excavation support. The results show that tunnel excavation destroy the original stress field of surrounding rock, the radial axial force of the tunnel releases, tangential stress concentrates, t and the tunnel top arch position forms an obvious excavation loop. After the tunnel supporting measures, the supporting measures bear some of the surrounding rock pressure, the surrounding rock stress is improved, the tunnel surrounding rock deformation is obviously reduced, the overall deformation of excavation section tends to be uniform, and the plastic zone around the tunnel has been improved. Therefore, the supporting measures have restrict effect on the deformation of surrounding rock.