Abstract: In this article, the demand of urban bus operation condition on vehicle power system is analyzed from an energy perspective. Based on the analysis, for Hybrid Electric Vehicle (HEV) with composite electric power supply system, a new method is proposed to assign the required power to each energy source. Using this method, an optimal matching of three energy sources, the motor, battery and super capacitor, is conducted, in which the fuel economy, energy conversion efficiency, the service life and cost of the electric power supply system are taken as the reference indicators. The simulation on redeveloped ADVISOR shows that the matched scheme can achieve the desired performance.