The invention provides an effective measure for radically curing landslides of road cutting side slopes. The method is to excavate grid trenches vertically and horizontally on the slope that has slipped or is likely to slide, and lay wooden piles at a certain interval at the bottom of the trench. Then fill the modified reinforced soil in the ditch, and form the modified reinforced soil blind grid after full compaction. The preparation of the modified reinforced soil is: first, the original soil is blended into lime soil according to a certain amount of ash, and then sprayed with an aqueous solution of expansive soil ecological modifier according to a certain proportion. Relevant dimensions of modified reinforced soil blind fence design must be calculated by slope stability. After the construction of the modified reinforced soil blind grid is completed, the slope soil modification construction is carried out according to the method of modifying the expansive soil with the expansive soil ecological modifier. The modified reinforced soil blind grid grid is connected with the modified soil on the slope to form a whole, which enhances the anti-sliding ability of the slope soil. The invention is suitable for controlling and protecting side slopes caused by special soils such as expansive soil in roads, railways, water conservancy, industrial and civil construction and other projects, as well as water and soil loss.