In order to protect river environment rationally, we investigated zooplankton and water quality in Beiyun River four times during 2009 and 2010, and analyzed the species composition, density, biomass, diversity index, and water physicochemical character. The results showed that there were 79 species of zooplankton in Beiyun River, including 12 species of Protozoa, 34 species of Rotifers, 23 species of Cladocera, and 10 species of Copepods. Rotifers dominated in spring, summer and winter, while Protozoa in autumn. The dominant species of the zooplankton were Rotifers and pollutiontolerant Cladocera species. The water quality in Beiyun River was generally poor. The total nitrogen, ammonium nitrogen and total phosphorus were the major pollutants in Beiyun River, with their contents 2.12-9.79 times higher than the standards of grade V national surface water environment quality of China. Most of sections in Beiyun River were moderately polluted, some sections were heavily polluted, and the water quality was at the middleheavy pollution level.