Efficient aggregation of distributed charge-discharge loads is a key method to realize the value utilization of energy storage resources of electric vehicle power batteries. In order to adapt to the high-dimensional and complex trend brought by large-scale electric vehicles connected to the grid, the intelligent contract technology is introduced in this paper. Based on the whole-process modeling of charging and discharging behavior of electric vehicles, the boundary of electric vehicles convergent operation is established, and then the hierarchical scheduling optimization method of electric vehicles load is proposed. The effectiveness of the model was verified by analyzing three typical scenarios of disordered charging, ordered charging and V2G ordered charging and discharging.