Abstract: A field survey in Lake Taihu was performed from May 2019 to September 2020 before a full fishing ban was implemented. We analyzed the community structure and diversity of fish by using Shannon-Wiener diversity index, Margalef’s species richness index, Pielou’s evenness index, analysis of similarity and abundance-biomass comparison curves. In total, 65 species were collected, belonging to 51 genera, 17 families, and 9 orders. Cyprinidae had the largest number of species, accounting for 55.38% of the total species captured. Tridentiger trigonocephalus and Anguilla marmorata were first recorded in Lake Taihu. Settled fish species were the most frequent of the three ecological groups, and pelagic fish species were the most frequent of the three habitat types, whereas carnivore and omnivore fish species were the most frequent of the five feeding functional groups. The catch per unit effort (CPUE) using gill net and cage net were 4 287.03±515.94 and 626.32±91.24 g·net^-1·12h^-1, respectively. Coilia nasus, Carassius auratus, and Cultrichthys erythropterus were the dominant species. The mean values of Shannon-Wiener diversity index, Margalef’s species richness index, and Pielou’s evenness index were 2.34, 2.10 and 0.68, indicating that its fish diversity level was moderate, with the fact of miniaturization of fish. ANOSIM (analysis of similarity) revealed that the fish species composition of Lake Taihu varied significantly in spatio-temporal distribution patterns (P<0.05). Abundance-biomass curves (ABC) of fish community indicated that the community was seriously disturbed. The study can provide a scientific basis for protection and management of fishery resources in Lake Taihu.