Undersea tunnels inevitably experience structural performance degradation due to chloride-induced damage and require appropriate evaluation of performance. This paper proposes a practical framework to evaluate the life-cycle structural performance, using the Markov chain model-based stochastic method and major deterioration analysis for global and local performance, respectively. The framework was successfully employed to diagnose a 50 years old immersed tunnel suffering chloride damage, and as a result the global and local structural performance over 100 years was clarified, and the rational repair countermeasure was considered more easily. In addition, the life-cycle structural performance can be evaluated more rationally by integrating the stochastic method and the chloride-induced rebar corrosion analysis. Conclusively, the proposed framework may be expected as an effective and useful solution to predict life-cycle performance of tunnel under chloride attacks.