Green roof with water storage function

The utility model relates to the technical field of green roofs, and discloses a green roof with a water storage function, the green roof comprises a roof and a parapet wall fixedly connected to the peripheral side of the roof, the parapet wall is provided with a collecting box with a top opening, the collecting box is provided with a drainage pipe, one end of the drainage pipe is communicated with the collecting box, and the other end of the drainage pipe is located on the ground; the end, located on the ground, of the drainage pipe communicates with a control valve. By arranging the roof, the parapet wall, the collecting box, the drainage pipe and the control valve, in rainy days, rainwater falls into the collecting box, the parapet wall supports the collecting box, when the weather is dry and the greenbelt needs to be watered, the control valve is opened, the rainwater in the collecting box is drained through the drainage pipe, and the greenbelt is watered; in the process, rainwater collected in rainy weat