Abstract: Poyang Lake is the largest freshwater lake in China, and a typical natural lake in the middle and lower reaches of the Yangtze River. Different habitat season landscapes can meet the needs of fish in different life history stages, so that fish resources show dynamic distribution characteristics. The 10-year fishing ban have been implemented in the Yangtze River basin, including Poyang Lake since Jan 1, 2021, to conserve the aquatic organism of the Yangtze River. In this study, we applied hydroacoustic analysis with Simrad EY60 split-beam echo sounder, to detect the spatial-temporal distribution of fish in Poyang Lake from 2020 to 2021. The results showed that more than half of the fish were 10—30 cm of body length in all three seasons, deduced from the fish target strength (TS) signal. However, the TS varied significantly among seasons (P<0.05), with the highest TS in winter (–51.0±14.13) dB and the lowest (52.71±9.95) dB in autumn. The horizontal distribution of fish density was not homogeneous, and also significantly different among seasons (P<0.01). The maximum density was 440.22, 169.19, and 554.18 ind./1000 m³ in autumn, spring, and winter, respectively. Vertically, the fish density decreased gradually from the bottom to the surface in autumn and winter, while the fish density in the surface and middle layers was higher than that in the bottom in spring. The fish density varied significantly in the same water layer among seasons (P<0.01). This study obtained the spatial and temporal distribution characteristics of fish in Poyang Lake by using hydroacoustic method at the beginning of fishing ban, and provided a reference for the study of fish resource in the region at a macro spatial scale under natural conditions. The results can also support for the evaluation of the fishing ban effect and the evaluation of biological integrity during the ten-year fishing ban in Poyang Lake.