Abstract: In order to study the stability of surrounding rock of roadway, considering the change of elastic modulus after damage, the limit equilibrium state analysis of surrounding rock mechanics state is carried out by using the unified strength criterion. The analytic expressions of damage zone radius and stress of surrounding rock are deduced. In the case study, the effect of elastic modulus of damage zone, intermediate principal stress and dilatation are analyzed by the theory of solution． The results show that the damage zone radius will be increased with the increase of dilatation coefficient; with the increase of the elastic modulus of damage zone, the radius of damage zone will be increased gradually and the peak of tangential stress will be decreased gradually and farther to roadway; the bigger the intermediate principal stress coefficient is, the smaller the radius of damage zone is, and the peak of tangential stress is larger and closer to the roadway.