To improve the mechanized improvement effect of compacted Leymus chinensis grassland, a mechanized improvement process for compacted Leymus chinensis grassland was proposed and a grassland root-cutting and soil loosening compactor was invented. By exploring the physical structure characteristics of the root-soil composite layer of Leymus chinensis grassland and the analysis of the integration of agronomy and agricultural machinery, a technology for the improvement of the root-cutting and soil-loosening of Leymus chinensis grassland was proposed. An oblique-handled root-cutting knife, a folding- wing loosening shovel, and a V-shaped compacting roller specially used for the improvement of compacted grassland were designed. A grassland root-cutting, loosening and compacting machine was integrated and created, and its operating performance was verified through grassland tests. The test results showed that the firmness of grassland soil after loosening operation and root-cutting and loosening operation were decreased by 59.99% and 59.77% respectively, the bulk density was decreased by 23.62% and 22.99% respectively, and the porosity was increased by 20.71% and 20.16% respectively, and the groove gap width, soil uplift height, ridge contour area, soil looseness, tillage rate and surface flatness after root-cutting and loosening operations were all smaller than those after loosening operations. The operating depth stability coefficients of loosening operation and root-cutting and loosening operation were no less than 95.17%, but at the same operating speed, the operating depth stability coefficient of root-cutting and loosening operations was always higher than that of loosening operations, and root-cutting and loosening operations were closer to the expected operating depth（15 cm）than loosening operations. The suppression operation can fill the groove gap generated by the root-cutting and loosening operation appropriately.