Abstract:According to the characteristic of the driving environment of the expressway tunnel,the length research scope of the tunnel section was established.Based on the risk ingredients of tunnels and the selecting principles of the evaluation index,the main factors of the tunnel driving environment were analyzed by using Delphi and clustering analysis method.A safety evaluation index system of tunnel driving environment was established,which contained three arrangements with six sub-factors in two aspects including road environment index and climate environment index.And the indices were analyzed and contrasted.The evaluation index system can be applied to the analysis and evaluation of the driving environment of expressway tunnel.