Based on the data of annual precipitation and seasonal precipitation of Karamay from 1957 to 2010, the paper used non parametric statistical test of Mann-Kendall and R/S method and the least square method analyzed the trend and Hurst index of average annual precipitation and season precipitation, and estimated the variation trend and sustainable features of future precipitation. The results showed that the average annual precipitation of Karamay has significantly increased, but the persistence of the increase is not strong; the trend of spring and autumn precipitation is similar with persistent of annual precipitation, summer precipitation has a decreasing trend and persistent; winter precipitation has a decreasing trend, but the decreasing trend is random.