The distribution of bacterioplankton in three typical tributaries (Zhuyi River, Meixi River and Caotang River) of Three Gorges Reservoir was investigated in summer of 2013. The correlation between the abundance of bacterioplankton and ecological factors was analyzed. The results showed that the abundances of bacterioplankton were significantly different in these rivers, ranging from 0.53×10⁵ to 10.55×10⁵ cells·mL^-1 with an average value of 2.71×10⁵ cells·mL^-1. The average abundance values were in order of Meixi River > Zhuyi River > Yangtze River > Caotang River. Vertical distribution of bacterioplankton biomass in three tributaries showed a similar change trend, being the highest in the surface water and the lowest on the bottom. The correlation analysis showed that DO, pH and chlorophyll-a had significant correlations with bacterioplankton abundance, indicating that these parameters are the main factors limiting the bacterioplankton abundance in this region. The waters surveyed were eutrophic according to bacterioplankton abundance.