V2G system can provide two-way controllable active power and reactive power into the power grid, realize the load fluctuation and stabilize the power grid peak power regulation function. This paper focuses on the power control of the V2G system in the grid-connected mode. The main circuit structure of the V2G system is introduced. To tracking current instructions precisely, the proportion feedback integral control method is proposed. The effectiveness of the proposed control strategy is verified by simulation and experiment results.