Abstract: Road traffic system is a complex,nonlinear and spreading clustering system.Some factors,such as changes of topology,model of travelers and natural environment could bring great influence on the service capacity of road network.This paper discusses the effect of road network vulnerability from the factors of the road,human and natural environment,and introduces the principle of the three-dem arcation analytic hierarchy process (TDAHP) which was used for quantitative analysis of these factors.The validity and rationality of this method were proved by the concrete examples,and the problems of reducing the vulnerability of the network and problems needed to be emphasized were found out.It is of certain value for engineering application.

Key words: road network vulnerability, influencing factors, three-dem arcation analytic hierarchy process