The article analyzed the concentration period and the characteristics of precipitation variation in Kuye, Tuwei and Jialu river basins of Yulin prefecture from 1966 to 2010, and used IDW(inverse distance weighted) to research the temporal and spatial distribution law,and took Mann-Kendall and moving t-test method to test its mutation and trend. The result shows that the overall precipitation of the area is about 400mm and is stability and slightly down. Precipitation was concentrated in middle July and was increased through upstream to downstream.The annual precipitation did not take place mutation in this area which is meaningful for the development of water resources and the improvement of ecological environment.