Abstract: Based on the monthly runoff data of two hydrological stations in the source area of the Yangtze River and the Yellow River from 1956 to 2012, the characteristics of runoff, including long-term trend, abrupt change and periodic variation were analyzed. The results show that the monthly runoff in the source area of the Yangtze River shows a single peak, the peak value appears in July, while it shows a double peak in the source area of the Yellow River, and the peak values appear in July and September respectively. The seasonal and annual average runoff in the source area of the Yangtze River experienced an upward trend in the past 57 years. On the contrary, the annual average, spring and autumn average runoff in the source area of the Yellow River experienced a downward trend, while the runoff variations in summer and winter showed an upward trend. The points of abrupt change of the Yangtze River in 1960 and 1968 are relatively reliable. Additionally, there may be an abrupt change around 1998. For the source area of the Yellow River, the abrupt change points in 1960 and 1968 have high reliability. There are 9~10a and 22a cycles of annual runoff in the source region of the Yangtze River, and 4a, 7~8a and quasi-16a cycles of annual runoff in the source region of the Yellow River.