The trends in the water and sediment loads of the main rivers in China are analyzed with the data till 2006 from the series publication of China Gazette of River Sedimentation
by using the water-sediment diagram. According to the trends in their annual runoff and sediment load entering to the sea main rivers in China can be classified into 4 groups:(1)rivers with stable water but decreased sediment loads,including Huaihe river and the rivers to its south;(2)rivers with decreased water and sediment loads,including Liaohe and the Yellow Rivers;(3)river with slightly synchronal decreased water and sediment loads,including Songhua river;and(4)rivers with greatly reduced water and zero sediment loads with example of Yongding river Most riverste the south of the Huaihe show no evident trend in their annual runoff,but dramatically decrease for their sediment load. Both water and sediment loads of rivers north of Huaihe river have the evident decreasing tendency. The recent 10 years the average values are only 1/3 of the long term average values for the Yellow River's runoff and 1/4 for its sediment load,and the water and sediment loads approach zero for the rivers in Haihe river system In general,the sediment loads of most rivers in China decrease evidently. The drops in the water and sediment loads of the rivers are mainly caused by human activities. The reduced sediment loads of the rivers in south China are more closely related to the reservoir construction,sand mining and soil conservation activities. The decreasing water and sediment loads of rivers in north China are mainly the results of rapid increased water consumption,reservoirs and their operation modes,and effects of water and soil conservation measures. It also shows that it has advantages using water sediment diagram in analyzing the trends in water and sediment loads of rivers.