Ecological construction is the foundation of sustainable development in "the Belt and Road" region. Longnan, Gansu Province, is an important water conservation region in the core area of "the Belt and Road" region, and frequent natural disasters, such as shallow landslides and debris flows are major geographical features of this area. The soil and root systems of four typical shrubs (Periploca sepium, Lespedeza bicolor, Ziziphus jujube and Punica granatum) were studied by single tensile test and direct shear test of remolded soil to explore the improvement of soil physical properties and shallow landslides. The results showed that the root system of these shrubs could significantly improve the soil water content and pore structure of the soil. There was a significant power function relationship between the tensile strength and root diameter (P < 0.01), and the tensile strength of the capillary root with diameter < 1 mm was the highest. The tensile strength of a single root was in the order of L. bicolor > P. granatum > Z. jujube > P. sepium. The shear strength of remolded soil decreases with an increase in water content, and the soil cohesion (C) and internal friction angle (φ) decreased with an increase in water content. At the optimal moisture content of 10%, the shear strength was in the order of P. sepium > Z. jujube > P. sepium > L. bicolor. With increasing root density, the shear strength of root soil composite system of P. sepium and L. bicolor decreased. The shear strength of P. sepium and Z. jujube reached the highest while it was under 1.5 times that of the natural root density. This study could provide a theoretical basis for vegetation restoration in "the Belt and Road" region by evaluating the effects of different shrub slopes in shallow landslide-prone areas.