The paper studies the characteristic of precipitation and variation tendency by using coefficient of non-uniformity of precipitation and the methods of anomaly analysis,5-year moving averages,linear estimation and hydrologic statistics based on the observed monthly mean precipitation data of He-Long reach,Long-San reach and San-Hua reach situated on the middle Yellow River in 1956-2000.The outcomes show that a) the annual precipitation of the middle Yellow River is 433-659 mm,uneven temporal and spatial dis...