Based on the typical battery management system（BMS）architecture for electric vehicles，the HAZOP analysis method and the methodology given in the national standard GB/T 34590-2017 Road Vehicle Functional Safety are used to carry out the battery management system hazard analysis and risk assessment. The functional safety objectives and functional safety requirements of the battery management system provide a reference for inheriting and refining the BMS technical security requirements and security architecture and the implementing of the functional security requirements of the BMS to the hardware and software design.