Abstract��The Zooplankton species composition��quantity distribution��diversity��community structure and relationship between abundance and environmental factors in Yueqing Bay based on the survey in May and September. The results showed that there were 13 groups 47 species of Zooplankton in May and 16 groups 70 species in September. The Zooplankton in the Survey area were mainly composed of coastal low saline species, and there were a few of brackish water species. The main species of May were Calanus sinicu��leurobrachia globosa��Sagitta bedoti Beraneck, and the main species of September were Centropages dorsispinatus��Sagitta nagae��Calanopia thompsoni��Euphausiacea larvae and Macruran Larvae. The abundances of zooplankton in May were 91ind /m3, and 115ind /m3 in September. The qualities of of zooplankton in May were 0.209 g/m3��and 0.222 g/m3 in September. The Margalef richness index�� Pielou evenness index��Shannon-Weiner diversity index and Simpson dominance index in September was more than in May. Through the study of the Zooplankton species composition��quantity distribution��diversity��community structure and relationship between abundance and environmental factors in Yueqing Bay is to provide evidence for ecological monitoring, evaluation, and provide scientific evidence for the development of the sustainable utilization of marine resources to the sea.