Abstract: Based on the basic idea of stochastic user equilibrium assignment and the traffic flow theory,the concept of road traffic state was introduced in order to describe the problem of traffic assignment.The road traffic state was defined as the linear weighted sum of travel time and traffic congestion degree.Based on the assumption that under stochastic variations of link capacities,passengers’ standard to choose a route is the minimization of travel time and traffic congestion degree,a stochastic user equilibrium assignment model based on road traffic state was proposed.The equivalence and uniqueness of the solution of the proposed model were demonstrated,and an algorithm for the model was given.The numerical results for a small traffic network show that the proposed model can reflect the passengers’ routing behavior in a stochastic road network.