Device for afforesting top of building

The utility model discloses a device for afforesting the top of a building. The device comprises a box body which is filled with a growing matrix, wherein the box body comprises a herbaceous plant growing region and a shrub growing region; permeating holes are formed at the bottom of the herbaceous plant growing region and are communicated with the shrub growing region; the shrub growing region surrounds the herbaceous plant growing region; the growing matrix in the shrub growing region is deeper than the herbaceous plant growing region; a water storage layer is arranged at the bottom of the box body, a partition plate with holes is arranged at the top of the water storage layer and is provided with a filter screen and a coarse sand layer; the growing matrix is arranged above the coarse sand layer. The device can save water evaporated and increase utilization of water. In addition, shrubs further provide shade to the device to prevent the device from being quickly aged under the effect of solar exposure.