Abstract: In order to solve the instability problem of the large section ingate with thin and weak mudstone roof and thick coal seam in Zhangcun Coal Mine, this art icle identified the causes of ingate damage with imaging observation of deep surrounding rock crushing condition by borehole camera, and used FLAC3D software to si mulate the surrounding rock failure process and analyzed the mechanism of ingate damage. Based on analysis results, reinforcement scheme of the damaged ingate W as proposed, including injecting cement inorganic material, recharging polyurethane chemical organic material and setting full-size grouted pre-stressed anchor cable. T he results showed that injecting two times respectively by two kinds of materials could enlarge the range of fracture flling, recover complete structure of broken rock an d improve the reinforcement effect greatly, yet setting anchor cable was equivalent to apply strength boundary condition to the surrounding rock, with a strong initiative t 0 resist re-deformation. The combination of the two measures could solve the repairing problem of broken ingate with thin and weak mudstone roof and thick coal seam successfully.