[Objective] The root distribution parameters of grass-shrub vegetation (Cynodon dactylon, Vetiveria zizanioides, and Amorpha fruticosa) on soil reinforcement on the banks of the canal of Ezhou airport were analyzed quantitatively to provide a theoretical basis for better evaluation of the effectiveness of vegetation root soil.[Methods] The root-drill sampling method was used to explore the changes in grass-shrub root distribution parameters at different depths. Indoor direct shear tests and outdoor tensiometer tests were carried out to study the effect of root distribution parameters on shear strength indices and matrix suction.[Results] ① The root distribution of grass-shrub vegetation generally decreased with increasing soil depth. The root distribution parameters of shrubs (A. fruticosa) and herbs (C. dactylon and V. zizanioides) were 2.13-2.90 times in the depth range of 0-40 cm. ② The cohesion of the shrub root-soil composite was significantly higher than that of the herbs, and the cohesion satisfied a polynomial function relationship with root length density (RLD) and root surface area density (RSAD). ③ RLD and RSAD had significant differences in cohesion and matrix suction (p<0.05). ④ There was an optimal root density for the RLD and RSAD of shrubs (A. pseudoacacia) to enhance the suction of the soil matrix.[Conclusion] The root systems of C. dactylon, V. zizanioides, and A. fruticosa can play a significant role in soil fixing. Owing to their root distribution, soil fixing depth, soil fixing methods, the three plants have different soil-fixing functions. The three plants can be combined for planting, which is not only beneficial to the stability of riverbank slopes, but also improves the soil erosion resistance.