The utility model discloses a photovoltaic afforestation composite roof's rainwater recovery system, photovoltaic afforestation composite roof include photovoltaic board, green plant and automatic drip irrigation system, automatic drip irrigation system includes drop irrigation pipe network, the collecting main, and drip irrigation main pipe, rainwater recovery system is including setting up at the side direction guiding gutter of photovoltaic board both sides, setting up horizontal guiding gutter, water catch bowl, rainwater drainage system and secret tank at photovoltaic board lower part edge, automatic drip irrigation system is connected with secret tank, low manufacture cost, horizontal guiding gutter makes the rainwater in the horizontal guiding gutter flow in in the water catch bowl, during rainwater drainage system is arranged in arranging secret tank with the rainwater of water catch bowl. The utility model discloses simple structure, simple to operate, with low costs can effectively reduce treatment process and applied cost that photovoltaic greening roof rainwater was retrieved.