In order to realize the control function of the pure electric vehicle and the self-cutting protection function of the high-voltage circuit, the high-voltage contactor that can be controlled and has the function of self-protecting and cutting off the high-voltage circuit must be configured in the high-voltage system of the electric vehicle. According to the requirements of the vehicle design, any electric vehicle will be equipped with a high-voltage contactor in the main power circuit. If the contact of the high-voltage contactor fails to close or open, there is no corresponding correct way to deal with it, which may cause abnormal malfunctions. Control and cause the car to not start normally or not to start. In severe cases, it will cause danger to the vehicle and personal safety. In view of the seriousness of the above problems, it is necessary to carry out safe and effective real-time monitoring of the contact state of the high-voltage contactor, and deal with the fault. When the high-voltage contactor contact fails to close or open, the high-voltage management system will issue an audible and visual alarm to prompt the operator and control whether the car can perform other operations according to the level of the fault.