Abstract: The modelling and solving of dynamic epuilibrium traffic assignment problem is a theoretical basis to develop the Intelligent Vehicle Highway Systems (IVHS). In this paper, a continuous time optimal control model for the multi-starting point and single-destination network, is formulated and its optimality conditions are proved to be equivalent to the dynamic user equilibrium principle. To avoid solving the complicated two-point boundary-value problem, a steady state-costate solution algorithm is proposed that generates an approximate solution to the network optimal control problem. This algorithm could make the full use of the advantages of the traffic and computer network structure, and would be computationally efficient for large networks. The test results on an example network is reported to demonstrate the performance of this algorithm.