Abstract: To study the correlation between water quality evolution and zooplankton community dynamics of Dongting Lake，this study conducted a systematic investigation of zooplankton communities at 11 typical sections of Dongting Lake from 2020 to 2024，with seasonal sampling in March (dry season) and September (flood season).Twelve environmental factors were simultaneously measured to reveal the dynamics of community structure，its correlation with environmental factors，and to assess aquatic ecological health.The results showed that a total of 2 phyla and 36 genera of zooplankton were detected in Dongting Lake.Rotifers (15 genera) were the absolute dominant group，accounting for over 97% of the total density (131.1 individuals·L^-1).Cladocerans (14 genera，2.1 individuals·L^-1) and copepods (7 genera，1.8 individuals·L^-1) had lower densities，indicating a significant "miniaturization" trend in the community.In terms of spatial distribution，the average zooplankton density in East Dongting Lake reached 160 individuals·L^-1，significantly higher than that in West Dongting Lake (126 individuals·L^-1) and South Dongting Lake (112 individuals·L^-1).This was closely related to the enrichment characteristics of total nitrogen concentration (1.67±0.37 mg/L) and chlorophyll a content (0.006 mg/L) in the region.The dominant species of the community were rotifers，including Polyarthra sp.，Trichocerca sp.，Keratella sp.，and Brachionus sp. Redundancy Analysis (RDA) results indicated that water temperature (WT)，total nitrogen (TN)，and ammonia nitrogen (NH₃-N) were the key driving factors regulating zooplankton distribution.Using the Shannon-Wiener diversity index and Pielou evenness index for aquatic ecological assessment，the results showed that the aquatic ecological status of Dongting Lake was moderate to good，with the Pielou evenness index performing better than the Shannon-Wiener diversity index.