Abstract: To study the community structure characteristics and influencing factors of zooplankton in Dianchi Lake, and to explore the changes in the zooplankton community during the process of eutrophication and the implementation of ecological restoration measures, monitoring and analysis on zooplankton communities and water quality parameters in Dianchi Lake were conducted in July 2021, and May, September, and December 2022.Based on the obtained data, the dominant zooplankton species were identified.RDA and Pearson correlation analysis were used to explore the relationships between zooplankton and water environmental factors.A comprehensive nutrient index was calculated to determine the nutritional status of Dianchi Lake.Historical data were collected to investigate the composition and changes of zooplankton over different periods in the lake.The study results showed that: ① A total of 66 species of zooplankton, belonging to 3 phyla and 39 genera, were collected in Dianchi Lake, with an average density of 2 073.44 ind./L.② Dianchi Lake was experiencing eutrophication, and the nutrient composition of the water body had a certain influence on the zooplankton.Significant positive correlations were observed between total nitrogen (TN) and chlorophyll (Chl.a) concentrations for dominant species such as Keratella cochlearis and Polyarthra.The total zooplankton density was significantly positively correlated with dissolved oxygen (DO), total nitrogen (TN), and chlorophyll-a (Chl.a) concentrations.③ During the process of eutrophication, the diversity of zooplankton decreased, while their density gradually increased, with small zooplankton gradually becoming dominant.④ After the implementation of ecological restoration measures, the number of species slightly increased, but no significant changes were observed in the dominant species.