In order to improve the micro-power quality as well as the running reliability, the storage unit from micro-grid is combined with active power filter. Taking the advantage of the similarity of main circuit structure and the complementary function between micro-grid energy storage unit and active power filter, this paper makes a combination to realize "one machine serves several purposes ", which can also save investment costs. It analyzes the structural characteristics of the combined device, gives the combination principle, establishes the combined overall system dynamic mathematical model, and applies space vector control strategy which can improve the control precision and response speed. The simulation and experimental results show that the device can achieve the purposes of adjusting active power and reactive power and suppressing harmonic of micro-grid, and verify the rationality and effectiveness of the combined device.