The basic characteristic of the battery electric vehicle of the Changsha metro line 2 were described. Main composition and characteristics of the electric drive system, auxiliary power supply system and network control system were introduced, and the main equipment and function of electric drive system were introduced in detail. Then, some of the new technology of the electric drive system was summarized. It has been proved that the system can achieve double power supply of catenary and traction battery, and has broad application prospects in the vehicle control performance, reliability, and environmental protection.