This paper analyzed the observed runoff series of Huangfuchuan from 1954 to 2010 by using a variety of methods. According to the analysis of concentration degree method, the annual distribution of runoff is severely inhomogeneous and mainly concentrates from July to September. The runoff interannual variation is greater.It used the moving average method and Spearman order correlativity check to prove that the trend of runoff was significantly decreased from 1954 to 2010. Through joint application of sequential cluster method and T test, it check out that runoff occurred mutation in 1983 and 1999. It also respectively analyzed the impact of climate and human activities on variation trend and mutation of runoff. The results show that runoff reduction of Huangfuchuan is mainly affected by the rise of temperature and human activities; The time of runoff downward mutation is largely in line with that of temperature upward mutation in 1983 and 1999. The influence of human activities on runoff changes is more and more.