Precipitation is the direct or indirect supply source of various water body in land. According to Qinghai lake basin precipitation data and using the three methods of Kendall rank time, Spearman rank time and linear trend regression test ,the paper calculated and analyzed the variation trend of precipitation in the basin ,and got the conclusion that the increase trend of precipitation is obvious, the decline of water level in Qinghai lake for ten years become slow because of the increase of precipitation. The result can provide reference for the prediction basin rainfall and water resources.