Simulated rainfalls, 1.69 mm min^-1 (high), 1.31 mm min^-1 (moderate) and 0.64 mm min^-1 (low) in intensity, were performed on plots of farmland, 2 m×5 m each in area and 10° in average slope gradient, on a red soil hill typical of hilly regions, to study on rules of migration,of sediments and enrichment of organic carbon therein. Results show that soil loss increased with rainfall intensity, and demonstrated a significant cubic relationship with volume of runoff, which is an important factor influencing soil loss on slope farmland; Sediment-bonded soil organic carbon is the mainly form of organic carbon lost with runoff, accounting for more than 84% and even 97.6% of the total loss of organic carbon. Organic carbon enrichment ratio of the sediments decreases gradually with increasing rainfall intensity, and selective migration of organic carbon was more evident in rainfalls low in intensity. In rainfalls, high in intensity, no significant linear relationship was observed between organic carbon enrichment ratio and clay enrichment ratio, but in rainfalls, moderate or low in intensity, an extremely significant or significant positive relationship was observed, respectively. Therefore, it can be concluded that rainfall intensity is an important factor that affects soil loss and migration of organic carbon with sediments.