In order to improve the power supply instability of photovoltaic power generation system, a new type of small power combined power supply system is designed, which includes the photovoltaic battery as the main body, the DC source and the lithium ion battery. Based on the hierarchical control of micro grid, a control method which is more suitable for system optimization is proposed,and the central controller and workshop controller are designed. In the MATLAB simulation environment, a complete simulation model of power supply system is built and the simulation study is carried out under different operating conditions. The results show that the system can quickly respond to the operating conditions. The system can quickly respond to the reasonable allocation of power distribution, complete realtime control. The simulation verifies the connectness the control strategy and the system power supply is intelligent and stability.