Climate change and human activities are two main factors affecting hydrological processes. Analyzing changes in streamflow and influence factors are of great significance for water resources management and comprehensive basin management, in the Chinese Wuding River basin. Hydrological and meteorological data in Wuding River basin were used to detect trends and abrupt changes in annual streamflow from 1960-2007, with the non-parametric Mann-Kendall test, cluster method for ordered samples, and Yamamoto method. IHA/RVA method was used to analyze hydrologic alterations. Water balance principle-based method was used to quantitatively assess impact of climate change on streamflow. A significant downward trend was found for annual streamflow, an abrupt change occurred in 1971. Streamflow regimes such as streamflow distribution, extreme flow (its time and frequency) were found to have changed to different degrees after abrupt change. Average flow in dry season, 90-day maximum and high pulses' duration within each year could be used as indicators for hydrologic alterations. It was estimated that climate change accounted for 36.57% of total reduction in mean annual streamflow from 1960-2007, the remainder was due to human activities.