Abstract: The aim of this study was to determine the shear strength of the root-soil composite system from sites with vegetation at different stages of degradation. The selected study area was the alpine grassland in Henan County, Qinghai Province, in the source region of the Yellow River. Shear strength tests were conducted to systematically analyze the characteristics of root-soil composite samples from sites with vegetation at different stages of degradation. The results showed that the grassland in the study area had an irregular oval-shaped pattern of degradation, with more severe degradation close to the center of the oval. From the outside to inside of the irregular oval, the grassland could be divided into a non-degraded (ND) area, a slightly degraded (SD) area, a moderately degraded (MD) area, and a heavily degraded (HD) area. As the degree of degradation increased, the diversity and abundance of local plants decreased, and introduced plants gradually replaced local plants and became dominant. The proportion of roots in soil and the shear strength of the root-soil composite system decreased with increasing degradation. The shear-strength thresholds of the root-soil composite system between neighboring degradation areas were also determined. The threshold of the cohesion of the root-soil composite system between ND and SD was 28.07 kPa, that between SD and MD was 20.46 kPa, and that between MD and HD was 9.21 kPa. This research to quantify differences in the strength of the root-soil composite system among grasslands with vegetation at different stages of degradation has theoretical value for further scientific studies, and will be useful for developing strategies to prevent and manage grassland degradation.