A new calculation method, which is different from the traditional structural calculation method for the secondary lining of the Metro tunnels constructed by the mining method, is proposed on basis of the analysis on the structural durability of the Metro tunnels constructed by the mining method. The proposed calculation method is based on the assumption that the primary reinforcement and the secondary lining bear the loads together and on the fact that such factors as the durability of the primary reinforcement are taken into account. According to the proposed calculation method, the structural calculation of the secondary lining is executed on basis of releasing the bending moment on the end of the primary reinforcement. The proposed calculation method is simple and convenient and can coincide well with the calculation model for the secondary lining of the tunnels constructed by the mining method.