In order to study the influence of the coupling effect of excavation damage and mining stress on the surrounding rock in tunnel engineering, based on the generalized Hoek-Brown strength criterion, the analytic solution expression of the thickness of the surrounding rock loosening zone considering the loosening effect of the surrounding rock is established, and three methods for determining the parameters of the strength criterion are proposed. Through comparative analysis of existing engineering cases, the accuracy of the proposed analytic solution is verified. The results show that: 1) The results calculated by the strength criterion parameters determined by combination 3 are significantly better than those corresponding to the other two combinations; 2) Under the equivalent method of different excavation radii, the results calculated based on combination 3 have high accuracy; 3) Compared with the iterative solution of the finite difference method, the calculation deviation of the analytic solution in this paper is less than 2% , and there is no need for complex numerical operations. The results can provide a rapid analysis tool for the evaluation of tunnel surrounding rock stability.