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Soil-root composites exsit in the degenerated grasslands with high compaction level. In order to break the soil-root composites effectively by mechanical means, the mechanical characteristics of soil-root composites were studied. The physical characteristics of soil-root composites were analyzed, including the compaction, bulk density, moisture content, porosity and root content. Shear strength, unconfined compressive strength and resilience modulus were measured and analyzed, and the influence factors were discussed, which were the bulk density, moisture and root contents. An orthogonal experiment was conducted to evaluate the effects of influence factors on the mechanical properties. The experiment results indicated that the composites in degenerated grassland aggravated soil compaction and gathered roots to distribute in shallow soil layer. The shear strength, unconfined compressive strength and resilience modulus varied with the change of bulk density, moisture content and root content, the interaction effects existed among these factors. The bulk density and moisture content showed significant influences on the internal friction angle (P<0.05). The cohesion and unconfined compressive strength were significantly influenced by moisture content (P<0.05). The shear and unconfined compressive strengths were strengthened as a result of the existence of root system, while its influence on resilience modulus was different. The composites were prone to be broken by mechanical means at high moisture content.