External shading system, main function of the system is the summer sun, cooling, make sunshine diffuse into the greenhouse, ensure the crops from strong light burns, while reducing 4 to 6 degrees Celsius temperature in greenhouse. Through the use of different rate of shading curtain or adjust the curtains, to meet the needs of different crops on the sun. Has the protective effect of hail suppression. The transmission way of the system with a wire rope drive and gear, rack, and a tiled, folding and other network for users to choose.