In order to explore the community structure of zooplankton in Xizi Lake and its relationship with environmental factors, the species structure,dominant groups and distribution of zooplankton in Xizi Lake were investigated in December 2014 while RDA analysis was conducted to grope for the nexus between dominant species and main water environmental factors. Totally 6 investigation sections which contained 18 sampling points were set in the national aquatic germplasm reserve of Xizi Lake. The results indicated that 33 species of protozoa(51.56%), 19 species of rotifer(29.69%), 7 species of copepoda(10.94%)and 5 species of cladocera(7.81%) were comprised. The dominant species of both core area and experimentation area were protozoa and rotifers. The range of zooplankton density was 1 755.25-7 023.38 ind/L and the average was 3 483.44 ind/L. The range of zooplankton biomass was 0.36-5.34 mg/L and the average was 1.67 mg/L. Community richness index(R) ranged from 1.02-1.96 while the average was 1.37; Shannon index(H') ranged from 2.02-3.47 and the average was 2.72; Evenness index(E) ranged from 0.59-0.85 and the average was 0.72. Under the common influence of both the degressive pressure of predators and the decrease of food resources, small individuals like protozoa and rotifers could benefit from the external winter circumstances of the reserve, and as a result, ecological dominance of zooplankton community were inclined to aforementioned groups. Besides, impacted by hydrological characteristics, the number and biomass of zooplankton species and diversity index of the southern part excelled those of the northern and central parts as a whole.