The safety of operating shieldbored tunnels has got more and more consideration as the tunnels deteriorate. The method to assess the safety conditions of tunnels has become the key issue for tunnel maintenance. In this paper, the indexes to express the tunnel behavior are proposed, the thresholds of the indexes are determined based on the tunnel performance, modified fuzzy comprehensive evaluation method (FCE) based on FCE method and analytic hierarchy process method are proposed by coupling the index correlation and irreversibility, and a case history is studied using the modified FCE method. 