Abstract: An urban ITS(intelligent transportation system) is built based on sensor networks to realize traffic intelligent control.Special ITS sensor node and associated hardware structure are designed,appropriate software is compiled,and an intelligent control model for urban traffic system is built,so that real time traffic information can be collected and processed for information distribution as well as scale coordination and control for vehicle routing.Matlab software is employed to simulate traffic information processing in the modeled system.It is shown that the modeled ITS can be put into practical application.It is characterized with higher cost performance,flexibility and control efficiency,comparing with the current ITS system based on GPS(global position system).