The invention relates to a method for greening a low-maintenance ecological slope roof, aiming at solving the problems that the greening soil of the slope roof easily runs away, and the green maintenance cost is high. The building slope roof comprises a structural layer, a waterproof layer, a heat insulation layer, a protecting layer, a root barrier layer, a drain layer, a water retention layer, a filter layer, an anti-skidding component, a light soil layer, a high-order aggregate soil culture medium and a greening vegetable layer. Due to a series of technology for preventing soil loss and reducing maintenance cost, the problem of slope roof greening can be thoroughly solved, and the aim of building a low-maintenance ecological slope roof greenery landscape can be achieved.