Abstract: Cladocera of 17 sampling locations in Bosten Lake were investigated 11 times from 2010 to 2013. Their community structure and succession dynamics were elaborated, and their responses to environment factors were analyzed. The results showed that a total of 14 species were identified and 3 of them were the dominant species. Compared with history data, species preferring oligotrophic conditions were decreasing or even disappeared, and species preferring eutrophic conditions had occupied the dominant position gradually. Spatial and temporal distribution of Cladocera densities changed greatly. Densities of the 17 sampling locations varied from 0-567.0 ind·L^-1 with an average of 30.0 ind·L^-1. Annual density of 2011 was the highest (82.5 ind·L^-1), and then decreased year by year. Horizontal distribution of Cladocera showed a significant difference, and it was higher in shallow water area along the coast than in deep water area in the center. Temperature was the main ecological factor affecting the Cladocera community. Species distribution changed with water depth, and Daphnia longispina was common in the deep water while Bosmina longirostris was common in shallow water. Food limitation and fish predation might be the important reason that caused the variation of community structure.