Abstract: A large number of micro-cracks exist in coal or rock mass.Its generation and expansion bring about the damage of coal or rock mass.The constitutive equation of isotropic elastic damage materials is applied to damage analysis of rock surrounding tunnel in this paper.The expression of damage effective functions and damage variable are obtained.The damaged radius and stress distribution are determined.The research achievement can be used to guide selecting tunnel support type and analysis of stability.The result shows that the damage of rock surrounding tunnel mainly depends on the natural stress.If the depth is shallower or tectonic stress is smaller,namely the natural stress is smaller,and then elastic deformation exists in rock surrounding tunnel.Otherwise,the isotropic elastic damage occurs.In addition,it depends on the mechanic properties of rock material also.