【Objective】Soil erosion is a main mechanism of land degradation. Much works have been done on sensitivity of coarse-textured soils to erosions different in degree, however, little is known about erosion mechanism of slopes of granite-derived red soil. An indoor simulation experiment was done to characterize runoff and sediment production on steep slopes of granite-derived red soil as affected by rainfall intensity and erosion degree and to explore erosion mechanism of slopes of coarse-textured soils.【Method】The experiment had flumes (3 m long, 1 m wide and 0.45 m high, each) packed with coarse-textured soil to simulate soil slopes different in erosion degree, two treatments in rainfall intensity (90 and 120 mm•h^-1) and two in inflow rate (2 and 2.66 L•min^-1). Based on field investigations and previous studies, the three slopes were designed to be slight (E1), moderate (E2) and severe (E3) in erosion degree, separately and all 16.7% in gradient, commonly seen in the hilly region in the sub-tropical climate zone of China. Before each run of the experiment, the flume was covered with a gauze to reduce the splashing impact of rain drops and then treated with a rainfall event low in intensity (30 mm•h^-1) till runoff appeared at the outlet of flume. Before each run, soil moisture content in the soil slope was determined with a soil moisture meter to ensure it was no more than 30%, and rainfall intensity and inflow rate was calibrated to ensure they were up to the set requirement of the test(±5%).【Result】Results show: (1) both rainfall intensity and flow rate played important roles in runoff formation and soil erosion. Runoff yield rate and soil erosion rate increased with rainfall intensity and inflow rate, and soil erosion varied in characteristic with slope erosion degree. The slope slight in erosion degree (E1) was most affected by rainfall intensity and inflow rate. (2) The slopes varied in erosion characteristics with erosion degree erosion. The slopes exhibited an order of E2 > E1 > E3 in runoff yield rate and an order of E3 > E2 > E1 in soil erosion rate. Multi-factor stepwise regression analysis shows that the higher the bulk density, the lower the runoff yield rate (R² = 0.8, P< 0.01) and the higher the clay content or the lower the silt content, the lower the soil erosion rate (R²=0.715, P< 0.01). (3) With rising rainfall intensity and scouring strength or inflow rate, gravel and clay contents increased, sand and silt contents decreased and fractal dimension of the sediment increased. (4) Fractal dimension was ultra-significantly and linearly related to the ratio of clay/sand in content.【Conclusion】All the findings in this study may provide a train of thought for evaluation of soil evolution under erosion and contents of the research on soil evolution.