Abstract: Taking Xining basin as example, the single root tensile tests, shear tests and roots anatomical tests of five species of shrub were carried out to study the relationship between mechanical characteristics of shrub roots and roots anatomical structures in the loess area of northeast Qinghai-Tibet plateau. The results showed that the main factors affected tensile and shear strength of single root including the percentage of phloem fibers and wood fibers, the degree and speed of periderm lignification. The shrubs single root elongation rate varied directly as the area percentage of secondary phloem, varied inversely as the area percentage of xylem. For five species of shrub, the largest area percentage of secondary phloem is Caragana korshinskii and reached 45% showing great single root elongation rate; the largest area percentage of xylem is Atriplex canescens and reached 50% reflecting the better mechanical characteristics. According to the root mechanical characteristics and root anatomical features, Atriplex canescens and Caragana korshinskii have a significant function in slope protection in Qinghai-Tibet plateau loess area.