Erosive rainfall is the main dynamic factor causing soil and water loss on the karst yellow soil slope. Using the measured data of 92 erosive rainfall runoff and sediment yield from 4 runoff plots from 2018 to 2020 at Huyangshui watershed in Zunyi City of Guizhou Province, this paper studied the response of runoff and sediment yield to bare slope and rocky outcropping plots under single rainfall events. The results showed that: (1) Erosive rainfall could be divided into three types A, B and C. A rainfall was the main type causing soil erosion on karst yellow soil slope. The standard of erosive rainfall was single rainfall＞6.6 mm or I₃₀＞3.6 mm/h. (2) On the bare slope, totally 63.27% of the erosive rainfall runoff depth was less than 0.4 mm, and 66.30% of the erosive rainfall soil loss was less than 1 g/m², and the soil erosion was mainly contributed by some single rainfall events. Contrasting the three types of rainfall, the law of runoff and sediment yield was as type A＞type C＞type B. (3) Soil loss amount was mainly determined by runoff depth, which directly determined the sediment yield on slope. 20 mm was a mutation value in type A rainfall leading to the apparent increase in runoff depth and soil loss on karst yellow soil slope. (4) Under the three types of rainfall, the plot runoff yield increased with the outcrop rate. That is to say, rock outcrop increased the runoff yield of the slope. But the change of sediment yield was complicated. In case of type A rainfall, sediment yield increased obviously with the outcrop rates of rocks. These results have great significance for the management of soil erosion and the establishment of soil erosion prediction model on karst slopes.