Abstract: When excavating a tunnel by TBM encounters geological disasters, such as large deformation, it usually poses risks such as jamming or limit intrusion.The research on safety evaluation of surrounding rock deformation during TBM excavation has an important practical significance in reducing the risk of jamming or limit intrusion.This paper analyzed the deformation characteristics of open TBM excavation tunnels, and established safety evaluation indicators and methods for deformation of open TBM excavation tunnels.By using three-dimensional numerical simulation and on-site monitoring of deformation, the deformation of surrounding rock in the shield zone and after the shield can be obtained, so we can achieve safety discrimination of deformation in open TBM excavation tunnels.Engineering applications in Xianglushan tunnel in Central Yunnan Water Diversion Project show that the proposed method can effectively identify the safety of deformation under different support schemes, thereby providing a basis for real-time adjustment of support schemes during open TBM tunnel construction.