The article analyzed the seasonal and annual distribution of rainfall erosivity using the data of rainfall collected in Small Cucumber Park Soil and Water Conservation Monitoring Station of Yuanmou County since the 1990s， and established a preliminary prediction model based on the daily rainfall erosion. The re- sults indicated that:the rainfall erosivity in the monitoring station mainly distributed in June to September.the peak appears in July, commonly annual rainfall erosion concentrated in several rainfalls，the rainfall erosivity between different years varied wildly, the great difference between the values is about 2. 6 times. We constructed a prediction model of the daily rainfall erosivity and testified that it is significant after regression analysis checking，which may be useful as a reference to the study of soil and water conservation in this region in the future.