The invention provides an abrupt slope spray-seeding greening method. The method comprises the following steps of clearing away loose stones and impurities on the surface of a slope; embedding grouting anchors in the abrupt slope, grouting for anchoring, inserting common anchors, and fixing by using reinforced belts; laying a geogrid, namely horizontally and longitudinally laying porous water pipes on the geogrid in a staggered way and laying an inverted filter on the geogrid and the porous water pipe until the inverted filter covers the porous water pipe; spraying a matrix and a seed mixture onto the inverted filter, or planting seedlings of plants in a matrix; laying a plant fiber net on the matrix and fixing by using a rattan net; laying a nonwoven geotextile on the rattan net; performing maintenance on plants, watering in an initial stage, performing drip irrigation in a later period, and removing the geotextile after the plants survive. According to the method, water and soil loss of the slope can be effectively prevented, the water-holding capacity of the laid green belt is high, the green belt is subjected to drip irrigation to save water resource, the slope can be greened in a short time, and the restored slope has a good greening effect and is stable in structure.