Abstract: Objective To investigate the effects of different rainfall characteristics and tillage practices on soil erosion and the particle size sorting of eroded sediment on gentle red soil slopes, and to identify the most suitable tillage practice for plateau gentle red soil slopes. Method Runoff plot experiments were conducted on gentle slopes in Malong District, Qujing City, Yunnan Province. Five treatments were established: downslope tillage (CK), contour tillage (T1), downslope + contour tillage (T2), downslope + hedgerow (T3), and downslope + soybean intercropping (T4). Four rainfall characteristic types were identified: Type I—moderate-duration, moderate-intensity rainfall; Type Ⅱ—medium-to-long duration, heavy rainstorm; Type Ⅲ—long-duration, light rainfall; and Type Ⅳ—short-duration, heavy rainfall. Five tillage treatments were established: downslope tillage (CK), contour tillage (T1), downslope + contour tillage (T2), downslope + hedgerow (T3), and downslope + soybean intercropping (T4). Four rainfall types were classified: Type I – moderate duration, moderate intensity; Type Ⅱ – medium-to-long duration, heavy rainstorm; Type Ⅲ – long duration, light rainfall; and Type Ⅳ – short duration, heavy rainfall. The effects of rainfall characteristics and tillage practices on slope erosion and sediment particle size distribution were investigated. Results (1) Rainfall characteristics were the primary factor controlling runoff and sediment yield, with contribution rates of 71.75% and 91.81%, respectively. Type Ⅱ rainfall generated the largest runoff depth (1.38 mm) and sediment yield (2.39 g/m²); Type Ⅳ produced relatively low sediment yield but the highest proportion of coarse sand (2–0.25 mm, 46.19%) in the eroded sediment. (2) Compared with downslope tillage (CK), the conservation tillage practices (T1–T4) reduced runoff depth by an average of 33.47% and sediment yield by 49.50%. Among them, T1 achieved the best runoff reduction (43.98%), while T3 showed the greatest sediment reduction (72.25%) and the smallest median particle size (0.09 mm), along with higher proportions of silt (37.05%) and clay (8.82%). (3) The maximum 60-min rainfall intensity (I₆₀) was the most critical factor driving sediment particle size distribution, with an explanatory power of 48.70%. ConclusionContour tillage (T1) is most effective for reducing runoff, whereas hedgerow (T3) is optimal for reducing sediment yield; both are effective soil and water conservation measures for gentle red soil slopes. Regional erosion control efforts should focus on the erosion risk associated with medium-to-long duration heavy rainstorms and adopt I₆₀ as a key early warning indicator. These findings provide a scientific basis for precise erosion control on sloping farmland in the mountainous regions of Southwest China.