As for the randomness and fluctuation of output power in grid-connected photovoltaic system，a single energy storage form cannot meet simultaneously the common needs of both power type and energy type. In this paper，a kind of compound energy storage control strategy based on SOC value of super capacitor for photovoltaic power generation system is proposed so to achieve smooth grid connection of photovol-taic output. Firstly，the effect of compound energy storage on the stability of PV grid connection is ana-lyzed. Then，the compound energy storage control strategy based on SOC value of super capacitor is intro-duced in detail. Finally，a simulation model is set up in Matlab/Simulink to simulate photovoltaic smooth grid-connection and constant power grid-connection. The feasibility of the composite energy storage control strategy is verified by the simulation result，which can cooperate well with photovoltaic grid-connection and play a prominent role in smooth fluctuation and peak cutting and valley filling.