Abstract: In this paper, Based on the measured data of summer mean flow from 1957 to 2016 at Zhimenda Hydrological Station in the source area of the Yangtze River, Plateau summer monsoon(PSM)and South Asian summer monsoon(SASM) during 1957-2016. The means of morlet wavelet method,catastrophe test and sliding correlation coefficient was adopted to analyze the variation characteristics of summer mean flow in the source region of the Yangtze River and its relationship with the PSM and the SASM. The results showed that in the past 60 years, the summer mean flow in the source area of the Yangtze River had shown an increasing trend. In 1957-1997, the summer mean flow was relatively less, and in 1998-2016, the summer mean flow began to increase. The summer mean flow in the source area of the Yangtze River had undergone a significant change from decreasing trend to increasing trend around 1995. There were significant positive and negative correlations between summer mean flow and PSM and SASM in the source area of the Yangtze River, and significant negative correlations between PSM and SASM. PSM and SASM influenced summer precipitation and runoff in source area through atmospheric circulation changes. Understanding of the relationships between PSM and SASM has important implications for the water resources management in the source regions of the Yangtze River.