To resolve the negative impacts with automobiles， people are focusing on studying new energy sources for automobiles. A hybrid power system of electric vehicle is proposed based on photovaltaic cells， ultracapacitors and batteries. In accordance with the characteristics of the three power sources， the paper designs a maximum power point tracking（MPPT） controller based on Boost circuit and a bidirectional DC/DC converter for connecting the ultracapacitors and the DC bus. Besides， the current restriction strategy is chosen as the overall control strategy of the system. The parameters of hardware circuits are decided according to simulation results using MATLAB. The experimental results show that the hybrid power system can achieve MPPT for the solar cell， and incorporate skillfully the high specific power of ultracapacitors and the high specific energy of storage batteries， so the time of sharp current discharging is reduced and the performance of starting up and accelerating for electric vehicle is improved.