The invention discloses a skylight-forming lining structure repair method for tunnels. A local skylight is formed after original flawed concrete is removed and then closed through layered mesh concrete after lining repair steel bars are embedded, and then the original flawed part and surrounding qualified linings are connected into a whole through anchor rods, steel bar meshes, steel bar drilling nails and mesh concrete. The skylight-forming lining structure repair method is mainly used for repairing the diseases that tunnel lining concrete severely lacks thickness or strength or voids are formed in the backs of the linings, is easy to implement and can be used for repairing lining structures, the repair method and process are fast and effective, the repair time can be greatly shortened, and the construction process safety and the structural safety can be guaranteed. The skylight-forming lining structure repair method is especially suitable for reinforcing the tunnel linings of railways in operation and can bring great economic benefits.