Soil anti-scourability of different vegetation types and the effects of plant roots on soil anti-scourability in Caijiachuan watershed of Loess Gully-Hilly Area in Western Shanxi Province were studied by using undisturbed soil scouring experiment, taking the soil of Pinus tabulaeformis forest, Robinia pseudoacacia forest, Armeniaca sibirica forest, Vitex negundo land and wasteland as research objects. The results showed that:(1) In the undisturbed soil scouring experiment, the trend of runoff of all vegetation types with the scouring time was not obvious, and the sediment concentration decreased at the beginning and then tended to be stable with time, while the index of soil anti-scourability showed a trend of increasing gradually. (2) The total root length density, root surface area density, root volume density and root biomass density of all vegetation types showed that Robinia pseudoacacia and Armeniaca sibirica forest land were larger, while Prunus armeniaca, Vitex negundo and wasteland were smaller and similar. There was a positive correlation between the total root parameters. Among the root indexes of different vegetation types with different root diameter ranges (0~0.5, 0.5~1.0, 1.0~2.0, 2.0~5.0, >5.0 mm), the root length density of 0~0.5 mm diameter root was the largest, and the root volume density of the fine roots was generally smaller than that of coarse roots. (3) Plant roots of different vegetation types can enhance soil anti-scourability. The enhancement effect was stronger in Robinia pseudoacacia and Armeniaca sibirica forestland, weaker in Armeniaca sibirica, Vitex negundo and wasteland. There were significant or extremely significant positive correlations between the root length density, root surface area density and root volume density of<1 mm diameter root and soil anti-scourability enhancement value among all plant root system indexes. There was no significant correlation between other diameter root parameters and soil anti-scourability enhancement value.