【Objective】 This study investigated effective precipitation process on key growth periods of winter wheat (jointing, heading, and milk ripe) under climate change in Shijin irrigation district to provide scientific basis for rainfall utilization and reasonable irrigation schedule.【Method】 Based on the hourly precipitation data from 15 meteorological stations in study area on April,May,and June from 1983 to 2012,the precipitation was classified according to duration and intensity. The occurrence time,frequency and amount of the four effective precipitation types (short light rain,long light rain,short moderate rain,and long moderate rain) in three growth stages of winter wheat were analyzed with the Mann-Kendall trend test and the inverse distance interpolation (IDW) method.【Result】(1) The occurrence time of the effective precipitation types was mainly from afternoon to morning (14:00 06:00),and long moderate rain mainly occurred at jointing stage during 10:00 15:00. (2) The trend and amount of all precipitation types were same. The short light rain increased at jointing and heading stages while decreased at milk ripe stage. Long light rain increased at jointing stage while decreased at heading and milk ripe stages. Short and long moderate rain types decreased during the three growth stages before 1998. After then, short moderate rain increased at heading and milk ripe stages and long moderate rain increased at jointing and milk ripe stages. (3) The spatial distribution of frequency and amount of the precipitation types was also identical. All precipitation types at jointing stage were high in north and low in south. At heading stage,the amounts of the short and long light rain types decreased from border to center, while the short and long moderate rain types increased from northeast to southwest. Distribution of short and long light rain types at milk ripe stage was consistent at heading stage. The amount of short moderate rain at milk ripe stage was high in north and low in south while that of long moderate rain was high in east and low in west.【Conclusion】 The frequency and amount of effective precipitation would increase at jointing stage and decrease at milk ripe stage of winter wheat under climate change.