To investigate the characteristics of the plankton community structure and evaluate the water quality and trophic status of the Chaotianmen to Fuling Section of the Yangtze River in summer. Nine sampling points were set up in this section in May 2022 to collect samples, and the physical and chemical indicators of water quality and the species composition, density, biomass, diversity and dominant species of plankton were analyzed. The results showed that: 1) The water quality in the Chaotianmen to Fuling Section was good, and the physical and chemical indicators such as dissolved oxygen content, total phosphorus content, ammonia nitrogen content, and chemical oxygen demand met the Class II water standard. 2) A total of 115 species of phytoplankton belonging to 43 genera in 5 phyla were detected, dominated by Bacillariophyta and Chlorophyta. The average density and biomass of phytoplankton were 54 500 individuals·L -1 and 0.189 2 mg·L -1 , respectively. A total of 50 species belonging to 33 genera and 4 categories of zooplankton were detected, among which Protozoa species accounted for the highest proportion, and the average density and biomass of zooplankton were 16.8 individuals·L -1 and 0.098 3 mg·L -1 , respectively. 3) The average values of Shannon-Wiener diversity index, Margalef richness index and Pielou evenness index of phytoplankton at all sampling sites were 3.275 4, 7.748 2, and 0.966 0, respectively and the average values of these diversity indices for plankton were 2.281 5, 3.780 2, and 0.905 3, respectively. 4) A total of 19 species of plankton species were detected as dominant species in the Chaotianmen to Fuling Section, including 10 plankton species and 9 zooplankton species. The results of the water quality evaluation based on the diversity index of plankton showed that the water quality type of the Chaotianmen to Fuling Section in summer was light pollution to beta-medium pollution. The above results indicate that the water quality in the Chaotianmen to Fuling Section is generally good, the nutrient status of the water body is anaerobic, and the composition of the plankton community is relatively stable.