Abstract: The paper aims to grasp the evolution characteristics and variation trends of runoff in the source of the Yangtze River. The authors used concentration, concentrated period, linear trend estimation, Mann-Kendall mutation testing, residual mass curves of coefficient of modulus to study runoff within the year, interannual and interdecadal trend changes, mutation detection and more or less cycle. The results showed that: runoff was significantly increased from 1956 to 2012 in the source region of the Yangtze River, and interannual variability of upstream was more obvious compared with that of downstream. Runoff concentration was mainly concentrated in 55%-85%, and upstream concentration was higher than that of downstream. Concentrated period of runoff were mainly distributed in late July and early August, and this trend became more postponed. Runoff was supplied by precipitation, snow and glacier melt for Tuotuohe station, and was supplied by precipitation, snow and glacier melt water, and groundwater for zhimenda Station. Since 2000, runoff went into the wet period in the source region of the Yangtze River, which increased 19.3% more than the annual average in Zhimenda station, and increased 53.8% more than the annual average in Tuotuohe station. Annual runoff mutation occurred in 2005 in Tuotuohe station, and in 1961, 1968, 2008 at Zhimenda station. Tuotuohe station had 1 complete more or less cycle, Zhimenda station had 3 more or less cycles.