Abstract: The integration of electric vehicle (EV) and the grid provides the support of the application of large scale electric vehicles (EVs). So it is necessary to design the structure of EV grid integration under different charging modes, locations and management methods. The control management mode of power grid to EVs is analyzed under different charging scenarios. Then the main aims of EV grid integration are presented according to the requirements of grid operation, and a unified EV grid integration structure with five control levels is proposed, which include the user management level, the local energy management level, integrated management level, the distribution system management level and the area grid management level. In addition, the communication structure in different charging scenarios and control strategies of every level are discussed. In the end, the simulation is carried out on a specific EV grid integration scheme, and results show that the charging characteristics of EVs will change significantly with information exchanged between EV and the grid. It is also pointed out that there are different solutions for EV grid integration, and the unified structure proposed in this paper provide reference for the design and application of these schemes.