For photovoltaic(PV)module output voltage instability problems, a shunt power conditioning device which uses super-capacitor as a energy storage component to improve the quality of the PV power generation system is brought forward. In the normal operation condition of the PV power generation system, the device can quickly inhibit PV module voltage fluctuation, which make the PV power generation modules only need to provide pre-configured unit factor constant active power to load. The device can also be used as an UPS power supply to provide load full power in a short period of time when PV module short-term power interruption occurrs. Simulation results show that the device not only can effectively improve PV module output voltage and power quality, but also enhance the reliability of the electricity load.