The large-scale Electric Vehicles (EV) uncontrolled charging behavior will increase the safety hazard of the power system operation, and a large number of EV charging and discharging control brings new challenge to energy management of the power system. In this paper, an improved EV charging and discharging distributed coordination dispatch control strategy based on Multi-Agent System (MAS) is proposed. It aims at the valley-filling, under the framework of the virtual price coordination mechanism, considers the distribution network three-phase balance, transformer capacity and node voltage constraint, and combining with MAS information interaction mechanism, adopts iterative correction of virtual price to achieve the intelligent charging and discharging of EV. Taking IEEE33 node system as an example, simulation and analysis verify the characteristics and effectiveness of the proposed method. This work is supported by National Natural Science Foundation of China (No. 51307019, No. 51377016, and No. 51477027).