[Objective] Root tensible mechanism of three aboriginal plants in the Central-western Inner Mongolia area was studied to provide references of species selection for soil and water consvervation.[Methods] Single root tension of three common plants of the midwest regions of Inner Mongolia area, Hippophae rhamnoides, Caragana korshinskii and Medicago sativa were tested with indoor instantaneous ultimate method.[Results] (1) Single root transient ultimate tensile strength of the plants increased with diameter; single root ultimate tensile strength decreased by power function with diameter increased; (2) When the root diameters were in the same size class between 0.19~2.89 mm, three species' single root transient ultimate tensile strength and modulus of elasticity ranked as:Hippophae rhamnoides >Caragana Korshinskii >Medicago sativa when the three plants' root diameter were less than 0.5 mm, the fine root had greater ultimate tensile strength and modulus of elasticity; (3) When the same tree species had the same root diameter, if soil had high moisture content, the average tensile strength of single was small.[Conclusion] It is important to consider both morphological characteristics and mechanical properties when choosing appropriate species for soil and water conservation. The levels of root reinforcement erosion resistance of Caragana korshinskii were better than that of Hippophae rhamnoides and Medicago sativa.