Abstract: In order to make the electric car battery pack safe and efficient, a pure electric vehicle battery management system is designed to meet the requirements of an electric vehicle for power battery.PIC microcontroller is used for each node in the system and all nodes are based on CAN bus to complete the real-time and efficient communication.The designed hardware circuit of the battery management system can achieve real-time measurement of the battery pack voltage, current, and single battery voltage and temperature.The data will be processed by software with initial SOC amendment integral method and OCV-SOC curve to complete the assessment of the remaining battery charge.