The utility model discloses a waterproof structure of a tunnel. The tunnel comprises a structure wall layer, 20-mm polymer waterproof mortar, a 4-mm wet-laying self-adhesion asphalt-based polyester felt waterproof roll and a protective layer from inside to outside in sequence. A circle of middle-buried steel plate waterstop belt and a circle of back-attached type waterstop belt are arranged inside the structure wall layer along an annular deformation joint of the tunnel. Steel plate putty waterstop belts and cement-based crystallization permeable waterproof paint are arranged along transverse and longitudinal construction joints. According to the waterproof structure, tunnel construction and underground construction water resistance are considered as a systemic project. The waterproof principle, the waterproof design, material selection, the waterproof construction process, waterproof construction management, waterproof construction team selection and the like are included in a waterproof system according to specific requirements and conditions of the project, and the built waterproof system is complete.