Roof greening is a special form of greening. It is a form of space beautification based on the top platform of buildings to store water, cover soil and create landscape. Make full use of space, save land; improve the moisture retention performance of the roof, save resources. At the same time, roof greening can also be combined with reservoir and rainwater infiltration, groundwater recharge and other measures to store the excess rainwater and reduce the loss. When the soil is dry, the accumulated rainwater can be used for irrigation to restore the natural water cycle process damaged by the building, compensate the natural vegetation occupied by the building, and restore the complete natural ecosystem.