To assess the current status of plankton and fish resources in the Enshi Section of the Qingjiang River Basin， surveys and analyses of aquatic biological resources such as phytoplankton， zooplankton， and fish were carried out in January， April， and July 2023 in the mainstem of the Enshi Section of the Qingjiang River Basin and its tributaries， which include the Changpian River， Xiaoxi River， Zhongjian River， and Mashui River.A total of 100 species （including varieties） of phytoplankton were identified in 8 phyla， with 28 species belonging to the Chlorophyta and 19 species classified as dominant within the Cyanophyta.The species diversity， density， and biomass of phytoplankton showed an upward trend.Zooplankton were categorized into 4 groups， comprising 40 families and 55 genera， with 25 genera of Protozoa identified as the most aboundant.Three species of zooplankton were found to be dominant， all belonging to the Protozoa.Although the number of zooplankton species increased， there were no significant changes in density or biomass.A total of 51 species of fish were collected， classified into 3 orders， 11 families， and 44 genera， with the Cypriniformes representing the largest number of species at 39.The dominant fish species included Rhynchocypris oxycephalus， Pseudorasbora parva， Opsariichthys bidens and Hemiculter leucisculus.The number of fish species in the Enshi Section of the Qingjiang River Basin decreased significantly compared to the historical data from 1987 and 1990， which recorded a total of 122 species.However， there has been an increase in species diversity compared to the survey data from 2020 to 2022， which identified 44 species.Fish in the Enshi Section of the Qingjiang River Basin tend to be miniaturized and exhibit low biodiversity.Rare fish species such as Rhinogobio ventralis and Spinibarbus sinensis， which produce drifting eggs， are in serious decline， but the population of rare fish that primarily produce adhesive eggs， such as Schizothorax davidi， Euchiloglanis david， and Procypris rabaudi， as well as economiclly important fish like Cultrichthys erythropterus， have shown signs of recovery.These changes are mainly related to the changes in hydrological conditions resulting from the development and construction of large-scale water conservancy projects.It is recommended that the habitat of stickleback egg-laying fishes， such as Schizothorax davidi， be protected and restored.Additionally， we recommend the regular implementation of artificial enhancement and the release of fishes species such as R. ventralis， S. sinensis， Hypophthalmichthys molitrix， and Aristichthys nobilis.These methods aim to improve aquatic biodiversity in the Enshi Section of the Qingjiang River Basin.