In this paper, it is on the basis of gaining the main influence factors of durability for in-service bridge, using recursive hierarchical structure of analytic hierarchy process, constructing the assessment models about durability for in-service bridge in bottom, middle and top levels, combining with weight modify technology and fuzzy mathematics theory, the assessment results durability state is gained finally. It can discriminate using actuality of bridge effectively, and it has been a good guide for maintenance of bridge by practical test.