[Objective] The influence of soil physical and chemical properties and root characteristics on soil detachment rate under different mixed herbs and shrubs was explored in order to provide scientific basis for the evaluation of ecological construction effect in the Loess Plateau. [Methods] Typical taproot shrub Caragana korshinskii, fibrous root herb Artemisia gmelinii and taproot herb Agropyron cristatum, and their composite community were selected as research objects, and the undisturbed soil samples were collected. Soil separation experiment was carried out at a slope of 15° with a flow rate of 36 L/min, the separation rate was estimate, and the related root and soil parameters were determined. [Results] The detachment rate of grass shrub combination was 73.58% lower than that of the single herb and shrub, and the erosion reduction effect of Caragana korshinskii and Agropyron cristatum was the strongest. Correlation showed that the main root factors influencing soil detachment rate were root length density and root weight density, the main factor of soil was aggregate content ＞0.25 mm, the root factor was one of the main factors affecting soil separation rate of herbaceous plants. And the soil separation rate under the combination of shrub and grass was dominated by both soil factor and root factor. [Conclusion] Herb-shrub combined root system can effectively improve soil anti-scour ability, among which the combination of root architecture of taproot system and fibrous root system has the strongest effect, and different root architecture combinations have different leading factors affecting soil properties and anti-scour.