[Objective] To study the adjacent tap root and root nodes of typical soil and water conservation plants Caragana korshinskii, Hippophae rhamnoides and Medicago sativa in the different diameters of bending resistance and bending strength in Midwestern Inner Mongolia, in order to provide a scientific basis for the study of the inner mechanism of the plant root network.[Methods] Using bending test of cantilever beam, the tap root and root nodes of three kinds of plants was investigated.[Results] In the test root diameter range of 1~5 mm, the bending resistance of three plant root nodes and adjacent tap roots were positively correlated with the diameters, and the of three plant root nodes and adjacent superior tap root was ranked as:C. korshinskii > M. sativa > H. rhamnoides. In the test root diameter range of 2~5 mm, the root node bending force of three plants was smaller than their adjacent superior tap root, and ranked as:C. korshinskii (21.87, 24.33 MPa) > M. sativa (10.69, 17.02 MPa) > H. rhamnoides (4.81, 4.95 MPa).[Conclusion] The capacity of the C. korshinskii root system to resist bending deformation is the best among three plants. The least bending strength differences have been found between H. rhamnoides root nodes and adjacent tap roots, indicating that the bending resistance of H. rhamnoides root system is the best at all levels, which is beneficial to the consolidation of root systems.