To investigate the larval and juvenile fish resources in channel connecting Poyang Lake and Yangtze River during spring and summer. This study conducted surveys at 27 sampling stations across three areas （Gutang， Huoyanshan， and Duchang） in spring（May to June） and summer（July to August） of 2024. Using a Type I shallow-water plankton net with 10-minute surface horizontal trawls. A total of 24，603 larval and juvenile fish specimens， representing 41 species from 12 families and 7 orders， were collected. The dominant species were Hemiculter bleekeri， Rhinogobius similis， Hemiculter leucisculus， and Hyporhamphus intermedius， accounting for 87.86% of the total catch. In terms of community structure， spatial analysis showed higher diversity in the downstream Gutang area compared to the other two regions. Temporally， diversity and richness indices were higher in spring than in summer， while the evenness index exhibited the opposite trend. Larval and juvenile fish abundance peaked at June. With the highest density recorded in June， where Hemiculter bleekeri was the most dominant species. Environmental factors varied significantly over time and redundancy analysis （RDA） revealed that water temperature， pH， and dissolved oxygen were the most influential environmental factors affecting the distribution of larval and juvenile fish. Coilia nasus and Hyporhamphus intermedius showed significant positive correlations with water temperature and pH， suggesting that suitable temperatures promote gonadal development and that weakly alkaline conditions favor fish growth and reproduction. In contrast， Pseudolaubuca engraulis and Rhinogobius similis were positively correlated with dissolved oxygen， reflecting that sufficient oxygen levels support feeding and reproductive activities. The study demonstrates difference in the species composition of larval and juvenile fishes in the channel connecting Poyang Lake and Yangtze River， and environmental factors significantly influencing the distribution of dominant species.