[Objective] As farming mechanization is developing rapidly in agriculture, more and more large-sized farming machines are running in farmlands, bringing high pressure onto the soils and making them higher in soil bulk density, and consequently lower in water and air permeability, which eventually lead to lower crop yields. Rotation with cover crops that have taproots going deep into the soil is believed to be an effective measure to improve soil structure and alleviate soil compaction. However, cover crops vary in adaptability to soil compaction with climate and soil properties. The objectives of this study were to investigate responses of cover crops different in species (modes) to soil compaction, and to verify which one is the best to adapt to soil compaction relative to region.[Method] A field experiment, laid out in a field of Vertisol in the Longkang Farm of Anhui, was designed to have two treatments different in soil compactness (not compacted vs compacted) and four cover crop treatments (Fallow, Alfalfa, Oil Rape, Radish + Hairy Vetch mixture). Soil bulk density, penetration resistance, shrinkage behaviors, and cover crop root systems were measured and analyzed for characterizing response of the root systems of the cover crops to soil compaction.[Result] Results show that in the compacted treatment, soil bulk density in the 0~30 cm topsoil layer (P<0.05) and soil penetration resistance in the 0~27.5 cm and 37.5~45 cm soil layers was significantly higher (P<0.05), and soil shrinkage behavior in the 0~20 cm soil layer was altered, relative to those in the non-compacted treatment. Besides, in the compacted treatment, Alfalfa, Oil Rape and Radish+Hairy Vetch was lower in root dry weight density in the 0~50 cm soil layer, but higher in root specific surface area; Radish+Hairy Vetch was higher in average root dry weight density, root volume density and root length density in the 50~70 cm soil layer than Alfalfa and Oil Rape, indicating that Radish+Hairy Vetch was higher than Alfalfa and Oil Rape in root penetration capability. In the compacted treatment, in terms of coverage and shoot biomass, the cover crops exhibited an order of Radish+Hairy Vetch > Oil Rape > Alfalfa. Compared with the cover crops in the non-compacted treatment, Alfalfa, Oil Rape and Radish+Hairy Vetch in the compacted treatment was 62.5%, 67.6% and 15.8%, respectively, higher in shoot biomass and 61.4%, 57.7% and 47.8%, respectively lower in root biomass.[Conclusion] In conclusion, the root systems of Alfalfa, Oil Rape and Radish+Hairy Vetch respond differently to soil compaction. Radish + Hairy Vetch is the most adaptable to soil compaction.