To understand the changes in fish community structure and diversity in the Zhenjiang section of the Yangtze River since the implementation of the ten-year fishing ban, this study conducted surveys once during the fish breeding period (April–July) and once during the fattening period (September–November) each year from 2021 to 2024. Over the four-year period, a total of 792 net hauls were conducted in the Zhenjiang section, collecting 3,908 fish weighing 575.62?kg. A total of 66 fish species were identified, belonging to 9 orders, 16 families, and 47 genera. During the study period, the fish assemblage in the Zhenjiang reach of the Yangtze River was dominated by omnivorous (carnivorous) species, freshwater resident species, and benthic fish, accounting for 40.91% (40.91%), 69.70%, and 43.94% of the total species, respectively. The dominant species were Parabramis pekinensis, Hemiculter bleekeri, and Saurogobio dabryi. The highest number of fish species was recorded in 2024, with 48 species, significantly higher than the 39 species recorded in 2023. One-way ANOVA results indicated significant interannual differences in fish community diversity. In 2024, the fish diversity, richness, evenness, and dominance indices were the highest. The diversity index in 2024 (3.04) was significantly higher (P < 0.05) than in the previous three years. The richness index (6.86) was significantly higher (P < 0.05) than in 2023, and the evenness index (0.79) was significantly higher (P < 0.05) than in 2022. The abundance/biomass curve results showed that after the implementation of the fishing ban, the fish community structure in the Zhenjiang section was generally less disturbed. However, in 2022, the fish community was moderately disturbed due to abnormally low water levels, leading to decreased stability. By 2024, the fish community had preliminarily reached a stable state. Cluster and NMDS analyses indicated that the fish community in the Zhenjiang section was grouped into two clusters: 2021 and 2022–2024. Compared with 2021, the relative abundances of small fish such as Pelteobagrus nitidus, Hemiculter bleekeri, and Xenocypris argentea decreased from 2022 to 2024, while the relative abundance of Coilia nasus increased, reflecting certain successional characteristics in the community structure. After the ten-year fishing ban in the Yangtze River, fish resources in the Zhenjiang section showed a gradual recovery trend, and the community remained relatively stable. However, the recovery of the fish community was not a simple linear progression but was simultaneously influenced by both the “fishing ban (positive)” and “extremely low water levels (negative)” factors. This study clarifies the basic characteristics and trends of the fish community in the Zhenjiang section since the implementation of the ten-year fishing ban, providing support for evaluating the effectiveness of the fishing ban and assessing the aquatic biological integrity index. It also contributes to the steady and long-term implementation of the ten-year fishing ban policy in the Yangtze River.