In order to improve the drivability and energy efficiency of electric vehicle (EV), more and more batteries are connected in series with high voltage which makes it necessary to monitor the electric parameters of high voltage system (HVS) to ensure the high voltage safety. A high voltage safety management system is developed to solve this critical issue. Several key electric parameters including pre-charge, contact resistance, insulation resistance and remaining capacity are monitored and analyzed based on the presented equivalent models. An electronic unit called high voltage safety controller is developed. By the help of hardware-in-loop system, the equivalent models integrated in the high voltage safety controller are validated and the on-line electric parameters monitor strategy is discussed. The real vehicle experiment results indicate that the high voltage safety management system designed is suitable for EV application.