A watershed model was established based on a field survey of a small watershed located in the Three Gorges Reservoir region

three simulated rainfall events which intensities were 60

90 and 120 mm/h on the watershed to study the process of runoff and sediment yield. The results showed that the runoff and sediment yield increased with the increase of rainfall intensity

but the runoff yield increased much faster than sediment yield. In each of the three rainfalls

the runoff showed the tendency of increasing initially before tending to be stable

but the sediment yield changed quite complicated. In each rainfall

both the cumulative runoff and sediment yield varied in a linear function law with the increase of rainfall duration. A fluctuation change of sediment concentration was showed in three simulated rainfalls experiments.