The invention discloses a roof greening structure constructed by using garden waste.The roof greening structure comprises a cover layer, a matrix layer and a drainage-storage layer from top to bottom;the cover layer is arranged in a mesh shape, and a fixed strip is arranged on the cover layer; a padding of the substrate layer includes the garden waste, straw, earthworm dung and turfy soil, and plants are planted on the substrate layer; the drainage-storage layer comprises a drainage structure, a support structure and a water guiding structure, and the drainage structure is arranged at the upper end of the drainage-storage layer; the support structure is arranged into a structure with alternate trapezoidal shapes and inverted trapezoidal shapes, and the top end of the support structure isprovided with a through hole; the water guiding structure passes through the through hole of the support structure, one end of the water guiding structure is arranged in the matrix layer, and the other end of the water guiding structure goes deep to the support structure.Through the above manner, the roof greening structure can effectively absorb garden waste, is beneficial to the reasonable allocation and recyccling of resources, reduces the environmental load, and has a good environmental protection effect.