Lake aquaculture net-enclosure culture had been existing over the last 35 years in the East Taihu Lake, which brought a lot of water eco-environmental problems, while it was abolished completely in early April 2019. To provide a theoretical and scientific basis for the restoration, protection and management of fishery resources in the East Taihu Lake, the fish community structure and its relationship with the environment were studied by multivariate analysis using the data collected from the field surveys in late April, July and October, 2019. Variations on the spatio-temporal distribution patterns and community structure of fish community were determined by using Shannon-Wiener diversity index, Margalef's species richness index, and Pielou's evenness index. The relationships between abiotic environmental variables and fish community pattern were investigated with gradient analysis, combining Monte Carlo test to determine limiting factors affecting fish community structure. In total, 39 species were collected, belonging to 31 genera, 10 families, and 4 orders. Cypriniformes had the largest number of species, accounting for 69.23% of the total species captured. Sedentary fish species were the most frequent of the three ecological groups, and upper 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. Carassius auratus, Acheilognathus macropterus, and Hemiculter leucisculus were the dominant species. The mean values of species number, catch, species richness, Pielou's evenness, and Shannon-Wiener index of fish community all showed significant differences in different months (P<0.05, April > July > October). Cluster analysis indicated that similarity was high (above 46.75%) in different months and stations, except station 1 and station 3 in October. ANOSIM (analysis of similarity) and SIMPER (similarity of percentage) analysis also revealed that the fish species composition in the East Taihu Lake varied significantly between April and October and the average dissimilarity was up to 59.41%. Abundance-biomass curves (ABC) of fish community indicated that the community was moderately disturbed. 21.0% of the variation in composition of fish community was explained by total phosphorus (TP) in the RDA analysis, which suggested TP was the main explanatory factor (Monte Carlo test P=0.036). At present, TP, pH and dissolved oxygen (DO) were key environmental variables for temporal variation of the fish community structure in the East Taihu Lake.