The invention discloses a method for treating a stony desertification area by using sphaghnum and robinia pseudoacacia, and belongs to the technical field of stony desertification treatment. The method comprises the following steps: soil preparation, planting pit adjustment, planting and management after planting. According to the method, interaction between the sphaghnum and the robinia pseudoacacia is utilized, on the one hand, a robinia pseudoacacia planting pit is divided into three layers, sufficient nutrients and water are provided for the robinia pseudoacacia, the water retention effectis achieved, water can be slowly supplied for plants, and a good growth environment is provided for the growth of the robinia pseudoacacia; on the other hand, the sphaghnum is strong in cold resistance, extremely strong in water absorption capacity, relatively large in biomass, capable of improving a soil structure and accelerating the recovery speed of the soil in the stony desertification area;and the method is simple, the water retention performance is strong, the water resources in the planting process of the stony desertification area are greatly saved, the soil of the stony desertification area can be improved for a long time, and the treatment cost of the stony desertification area is reduced.