The research of using wireless sensor network to settle the problem of urban traffic has become a hotspot in the fields of intelligent transportation system. In this paper, a wireless sensor network model based on mobile agents is proposed. Since mobile agents have characteristics of autonomous collaboration and asynchronous interaction, this model owns the abilities of adapting to the dynamic network changes, reducing the network load and enhancing the data fusion. In the application of the model, the travelers can be guided to choose the right road line through calculation of the predicated value of traffic congestion, so the condition of the traffic congestion can be remitted in some way.