Abstract: For some tunnels, secondary linings are used to carry loads. In this paper, a method is presented to assess the reliability of composite linings during the service life of tunnels. A pulse process is proposed to describe the degradation of reinforced concrete linings. Based on construction records, in-situ monitoring data and finite element analyses, Response Surface Method is adopted to obtain the explicit expressions of load effects. A strict formulation for reliability analysis is given. Finally, the proposed method is demonstrated with an example.