Planar roof greening device

The utility model relates to the technical field of roof greening, in particular to a plane roof greening device which aims at solving the problem that rainwater collection and greening maintenance of plane roof greening are difficult and comprises a greening box, a substrate layer, vegetation, an annular water tank, a water pump and a spraying pipe. The top of the greening box is not covered; a substrate layer for planting is arranged in the greening box; the vegetation is planted at the upper part of the substrate layer; an annular water tank is annularly arranged on the lower portion of the greening box along the outer wall, the annular water tank and the greening box are independently arranged, and later maintenance is facilitated; the water pump is arranged in the annular water tank; one end of the spraying pipe is connected with a water outlet of the water pump; the other end of the spraying pipe is closed and arranged at the top end of the greening box; a plurality of spraying holes are formed in the p