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Natural grasslands with rhizome-type or rhizome-sparse grasses such as Leymus chinensis as the established species are in serious degradation. Mechanical soil loosening is one of the important means to improve this type of grassland. However, inappropriate methods of soil loosening can easily damage the grassland vegetation, and lead to soil desertification. In order to explore the suitable soil scarification method for improving degraded Leymus chinensis grassland, a method of loosening the soil by cutting roots to release pressure was proposed. Taking the degraded grassland in Hailar area as the research object, a comparative test of traditional loosening, loosening the soil along the cracks, and loosening the soil by cutting roots to release pressure was carried out by using a combination of discrete element simulation and field test. The effects of three loosening methods on the grassland disturbance process, work quality and loosening resistance were analyzed. The simulation results showed that loosening the soil by cutting roots to release pressure had a better loosening effect on the soil than traditional loosening and loosening the soil along the cracks. It improved the fluidity of the inner soil and reduced the disturbance of surface soil. Comparing the simulation results with field test, the results showed that the change trend of the loosening resistance of the tillage parts after the three loosening methods were consistent. The method of loosening the soil by cutting roots to release pressure had the smallest soil loosening resistance, the simulation result was 3692.75N, and the field test result was 4677.84N. The traditional loosening method had the highest loosening resistance, the simulation result was 5348.80N, and the field test result was 6489.40N. The loosening resistance of the method of loosening the soil along the cracks was between the two, the simulation result was 4713.33N, and the field test result was 5433.24N. The results showed that loosening soil by cutting roots to release pressure method had a better drag reduction effect. Field test results showed that soil loosening methods had a significant impact on work quality. In the soil layer with the same tillage depth, by comparing the traditional loosening and loosening the soil along the cracks, the soil compactness after loosening the soil by cutting roots to release pressure was decreased by 6.19% and 12.67%, respectively, and the mean soil bulk density was decreased by 1.19% and 3.16%, respectively. At the same time, loosening the soil by cutting roots to release pressure method caused the least disturbance to the surface soil and had a better soil loosening effect. The average values of the soil disturbance coefficient and soil bulkiness after the operation were 49.05% and 25.81%, respectively. The research results can provide an important basis for proposing soil scarification improvement technology for degraded Leymus chinensis grassland and optimizing the design of grassland scarification improvement equipment.