Crustacean zooplankton community in Lake Bosten was monitored and the impacts of environmental factors on curstacean zooplankton community structure were assessed during Jun.-Nov.2010 and Jan.2011.Results showed that crustacean zooplank-ton was mainly dominated by Cladocera, not only in species number, but also in density and biomass, with dominant species suc-ceeding seasonally.In summer, crustaceans were dominated by large-sized Daphnia cucullata and Diaphanosoma brachyurum.With the decrease of large-sized zooplankton in fall and winter, the percentage of small-sized Bosmina coregoni increased, sugges-ting that competition works between zooplankton of different body size.Regression analyses indicated that crustacean biomass and mean body length were positively correlated with water temperature.Correlation analyses revealed that the biomass of B.longirostris and D.cucullata was positively correlated with transparency, but negatively with Chl.a, indicating these two dominant species be-ing inhibited by the overgrowth of phytoplankton.Multivariate statistical analyses showed that 56.8% of the total variance in crus-tacean community structure was explained by environmental factors, with water temperature being the most important factor and wa-ter depth the second.High water temperature favoured the development of cyclopoids, D.cucullata and D.brachyurum.Mean-while, B.coregoni preferred to flourish in shallow stations while D.cucullata and D.brachyurum in deep stations.The difference in distribution pattern of dominant species might be due to the fish predation.