The invention discloses a tunnel lining steel rail reinforcing structure and a construction method. The invention aims to solve the technical problems of weak bearing capacity and poor safety of a lining structure after reinforcement. The reinforcing structure involves steel rails, connecting steel bars, U-shaped hoop ribs, steel bar meshes, foot locking anchor rods and steel fiber injection concrete, wherein the steel rails are adaptive to the cross-sectional shape of the tunnel lining and extends from one side wall to the other side wall, the connecting steel bars are longitudinally arrangedand are fixed firm to the steel rails, the U-shaped hoop ribs are arranged in the circumferential direction and fixed firm to the steel rails and the lining, the steel bar meshes are longitudinally arranged and fixed firm to the steel rails, the foot locking anchor rods are correspondingly arranged on wall feet on the two sides of the steel rails and are anchored to the steel rails and the lining, and the steel fiber injection concrete is sprayed on steel rail faces. The tunnel lining steel rail reinforcing structure and the construction method have the advantages that the process is simple,the applicability is strong, the lining structure is firm, the stress is better than the reinforcement of lining steel belts and the reinforcement of the lining net spraying, and the overall structureis firmer.