Crustacean zooplanktons were seasonally sampled at 11 sites in Lake Liangzi from August, 2006 to March, 2008. Totally 22 crustacean species, which were composed of 16 Cladocera species and six Copepoda species, were identified. These species belong to nine families and 18 genera, nine of which were recorded for the first time in this lake area. Analysis of the species dominance index (Y), Shannon-Wiener diversity index (H), number of species (S), species richness index (D) and individual density (ind./L) revealed significant seasonal variation of the crustacean diversity. Daphnia hyalina (Y = 0.80±0.01), Daphnia cristata (Y = 0.50±0.03) and Bosmina longirostris (Y = 0.58±004) were the dominant Cladocera species in spring, summer and autumn-winter respectively. Neodiaptomus yangtsekiangensis (Y = 0.41±0.01), Cyclops vicinus (Y = 0.46) to Neutrodiaptomus incongruens (Y = 0.65±0.18) were the dominant Copepod species in summer, autumn and winter-spring respectively. Population density of Crustacean declined gradually from 292 (±85, S.D.) to 169 (±104), 140 (±53) and 120 (±0) through spring to winter. Similarly, species diversity remained low in winter and spring (S ≤ 12, D = 0.77 and 0.71, H = 1.79 and 1.45, respectively), but increased in summer and autumn (S ≥ 17, D = 0.98 and 0.88, H = 1.78 and 1.83, respectively). Further analysis indicated that species composition and diversity indexes of Crustacean community were relatively stable between 2006 and 2007 summers (August), as well as between 2007 and 2008 springs (March). Our results indicated that Lake Liangzi was in good condition for Crustacean species.