Method for cultivating crops on roof

The invention discloses a method for cultivating crops on the roof. The method includes steps of manufacturing a light water-storage cultivating tank, preparing light cultivation medium, mounting a water level adjustment controller at the position of a water inlet pipe of the light water-storage cultivating tank, controlling the water level of the cultivating tank at the required height by the water level adjustment controller, paving the prepared light cultivation medium in the cultivating tank, and planting the crops to be cultivated into the light cultivation medium, wherein the light water-storage cultivating tank comprises a cultivating tank frame inlaid or arranged in a groove bed and a flexible waterproof material layer enclosing the cultivating tank frame, and the light cultivation medium comprises inorganic bearing materials and organic nutrition matrix. The method has the advantages that resources are sufficiently utilized, water and energy are saved, mounting is convenient, cost is low, the roof can be sufficiently utilized, safety of the roof structure is guaranteed and the like.