Abstract: Power Li-ion Batteries are the assistant power source for fuel cell hybrid vehicles, so a reasonable management to the Li-ion battery is vital to the vehicle. In this paper, some function modules were analyzed based on a module thought about the vehicle performance demand, then, the hardware system and the software system which were based on the RTOS μC/OS-II were designed. The system has been proven to meet the demand of stability and quick responding, and it makes a pleasing effect when putting into practical.