Based on the historical data of fish catches and fyke nets investigations on fish assemblage from 2017 to 2018 in different lake regions of Lake Hongze, the characteristics of fish community structure and dynamic variation of fishery resources were analyzed. The results showed that only 51 species (belonging to 41 genera, 16 families and 10 orders) were collected and Cypriniformes had the largest species number, accounting for 62.7% of the total species captured. Aristichthys nobilis, Hemiculter leucisculus, Carassius auratus, Coilia nasus, etc. were the total 7 dominant species in the lake. The Margalef richness index, Shannon-Wiener index and Pielou evenness index were medium in the whole lake, with higher values in the estuary and central region than two bay areas. Compared with historical data, the composition of fish community and the dominant species had changed, and the miniaturized tendency of fish resources was more obvious. Overfishing, water-level fluctuation and water pollution are potential main reasons for observed shifts in the fish assemblage.