Using simulated rainfall experiment, interill erosion and rill erosion on slope farmland of loess area were researched through putting nylon net cover on runoff plots to eliminate raindrop kinetic energy, increasing raindrop falling height to increase raindrop kinetic energy and turning up the soil as the contrast tests. The results showed that erosion and sediment can be divided into 4 stages, that is, raindrop splash, interrill erosion, rill erosion and runoff erosion after raining. After eliminating 99.6% of raindrop kinetic energy, interrill erosion and rill erosion were obviously reduced, interrill erosion was decreased by 35-61% and rill erosion was reduced by 35-64%. In addition, affecting mechanism of raindrop kinetic energy on interrill erosion and rill erosion was analyzed.