Abstract: Electric vehicle（EV） is a cross-domain subject with dual properties of traffic tool and mobile load. Large-scale centralized charging of EV will impact the power grid and aggravate the traffic congestion. Thus, the spatio-temporal optimal dispatch strategy for the EV charging load based on the interaction of vehicle-road-grid is proposed to regulate the charging behavior of EVs. Firstly, the dynamic traffic network model and the modified Floyd algorithm are used to simulate the EV driving path for predicting the spatio-temporal distribution characteristics of EV charging load. Secondly, based on the prediction results,the optimal dispatch strategy based on the Stackelberg game is proposed combining with the electricity price response degree model for the multi-objective optimization of the benefits of power grid, traffic networks and EV owners. Finally, a regional traffic network in Beijing, China and the IEEE 33-bus distribution system are simulated to verify the effectiveness of the proposed model.The results demonstrate that the proposed optimal dispatch strategy can not only realize the balanced distribution of load in time and space among charging stations, but also can improve the traffic flow of the traffic network around the charging stations and reduce the charging cost of EV users.