A rational fuel-cell power following strategy is made according to values such as vehicle fuel-cell power, battery power, and SOC (state of charge) of a lithium-ion battery; in the same time window, effects of different fuel-cell power growth rates on SOC of the lithium-ion battery are tested according to vehicle requirements; and at the same fuel-cell growth rate, effects of different time windows on SOC of the lithium-ion battery are tested according to vehicle requirements; a proper time window and a proper fuel-cell power change rate are found, so that the SOC value of the lithium-ion battery fluctuates within a certain range. The present invention can achieve a good operation mode of power distribution between the fuel cell and the lithium-ion battery, ensuring rational utilization of resources, thereby extending the application range of the lithium-ion battery to the maximum extent.