Abstract: As an important facility in the mine, the long-term stability of the surrounding rock in the permanent chamber of the mine is crucial for the safe production of the mine. In response to the technical problem of instability and difficult control of large deformation of the surrounding rock of the central auxiliary water chamber in Yidong Coal Mine, the deformation and failure characteristics of the surrounding rock of the auxiliary water chamber on site were sorted out, a UDEC numerical calculation model was established, and the stress, crack development degree, and deformation and failure characteristics of the surrounding rock of the chamber under the original concrete arch support were analyzed. The deformation and failure mechanism of the surrounding rock of the auxiliary water chamber was comprehensively analyzed. The results indicate that the main reasons for the difficulty in controlling the large deformation of the surrounding rock are low original support strength, uncoordinated support system, and expansion of the bottom plate when encountering water. Based on the actual on-site conditions and numerical simulation inversion results, a combined support technology of "grouting reinforcement + anchor bolt, cable + reverse arch" is proposed for repair practice. On site monitoring shows that within 45 days after repair, the maximum convergence of the two sides is 55.8mm, and the maximum displacement of the top and bottom plates is 46.5mm, which meets the requirements for safe use of the auxiliary water chamber and ensures safe production in the coal mine.