Abstract: To evaluate the variation of the relationship between rainfall and sediment yield,the trend of the sediment discharge pouring into Yellow River is of significance for the layout of flood control and sedimentation reduction system,as well as the determination of the Yellow River governance strategy. Four watersheds including the Jialu River,Qiushui River,Yanhe River and Malian River in the middle Yellow River are selected,and long series of hydrological data are used to analyze the variation characteristics of the relationship between rainfall and sediment discharge of the watersheds in different periods. The sediment discharges of hydrologic control station of each watershed are predicted on extreme rainfall conditions affected by the current underlying surface. The results show that the annual sediment discharge in the four river basins all present a decreasing trend. The highest decreasing magnitude reduction rate of the sediment discharge takes place in the Yanhe River. The annual effective rainfall in four watersheds is characterized by obvious stages,and the recent effective rainfalls are larger than the average values of accumulated year. For the three watersheds in the Hekouzhen-Longmen Reach,the relationship between the effective rainfall and the sediment discharge in the current period has changed significantly compared with the reference period,and the sediment-producing capacity has reduced evidently. The relationship between sediment discharge and graded rainfall is established,which can reflect the influence characteristics of different levels of rainfall on the sediment discharge in reference and current period. The effects of precipitation grades on sediment transport of the four watersheds in the current period are significantly lower than those in the reference period.The proportions of heavy rain and storm rain in Jialu River,Qiushui River and Yanhe River have increased from 38%～46% in the reference period to over 68% in the current period,and the high intensity rain has performed still as the main driving force for the sediment transport.The contribution of rainfall below moderate to the total sediment discharge has decreased significantly or even disappeared. The relationship between rainfall and sediment discharge in the Malian River watershed has changed very little,and the reduction in the impact of precipitation grades on the sediment discharge is less than those of three watersheds in the Hekouzhen-Longmen Reach,indicating that the risk of rainfall erosion intensity remains serious. Based on an analysis of hydrological frequency and the combination of historically measured extreme rainfall,the designed extreme rainfall conditions are proposed. Our calculation indicates that the possible incoming sediment discharges of Jialu River,Qiushui River and Yanhe River would be 27 million tons,25 million tons,and 0.30 million tons,respectively,and the sediment discharges have reduced by 83%～91% compared with the reference period on the condition of the current underlying surface. Since the increased sediment yield induced by the riverside-bank or the gully-bank and the limited water-and-soil conservation measures of Malian River,the sediment reduction ratio of Malian River is 48% and the possible incoming sediment discharge would reach above 150million tons.