Abstract: To reduce conflicts of branch line traffic flow and trunk road traffic flow in urban traffic networks, a region coordination fuzzy control algorithm is proposed in this paper. It is based on the control theory of classification and coordination of the system engineering. In the paper the design idea of coordination control and the control structure is introduced with emphasis. The algorithm simulation has been carried out through microscopic transportation simulation software Paramics and the result indicates that the region coordination fuzzy control algorithm can effectively scatter the traffic in urban traffic networks. Thus, it has confirmed the feasibility that this algorithm can apply to controlling the traffic flows in urban traffic networks.