In order to determine effects of structure characteristics and shear strength of red soil on soil detachment, relationships of soil detachment rate with soil aggregate characteristics and shear strength of the red soil were studied through indoor simulated erosion experiment with concentrated flows. Eight typical types of red soils were chosen for the study. Results show that aggregate stability index (As) integrated main mechanisms of aggregate breakdown, and was found to be well related with soil detachment rate under different flow shear stresses; A positive linear relationship was observed between saturated soil shear strength (σ_s) and critical flow shear stress (τ_c) in concentrated flow. By introducing As and σ_s into the WEPP (Water Erosion Production Project) model of rill erosion, a prediction equation of red soil detachment rate was established with a good correlation coefficient ( R ² = 0.8871). The study provides a new approach to research on erosion mechanisms of red soil, which is of great significance to perfection of the physical process model of soil erosion.