Abstract: In order to understand the current status and temporal distribution of early-life-history-stage fish resources associated with environmental factors and hydrological processes in the Luzhou reach of the upper Yangtze River, The middle of the "National Nature Reserve of Rare and Enemical Fish in the Upper Reaches of the Yangtze River", Luzhou section of the upper reaches of the Yangtze River, is a key area for the protection of fish resources and an important habitat and migration channel for fish. In order to accurately assess the status of early fish resources in the lower reaches of the dam after the impoundment of the Jinsha River cascade projects, understand the status of early fish resources in the Luzhou section of the upper reaches of the Yangtze River, and explore the impact of environmental factors and hydrological processes on early fish resources, fish resource surveys primarily on collecting drifting fish eggs and fry were carried out in the Luzhou section from May to July in 2019 and 2020. The temporal changes for the density of the egg and larvae as well as the relationships with hydrological indicators were then subsequently analyzed. During the investigation, a total of 2 153 fish eggs and 1703 larvae were collected. There were 18 fish species belonging to 2 orders, 3 families and 15 genera were identified through molecular biology methods. The dominant fish populations for the two years both were Rhinogobio typus, Pseudolaubuca engraulis and Coreius heterokont, the spawning amount of which accounted for 52.25%, 13.51%, 9.91% of the total in 2019 and 25.44%, 17.98%, 29.39% in 2020, respectively. The average fish larvae density was 0.31 ind./100 m³ and 0.78 ind./100 m³ in 2019 and 2020, and the peaks appeared in late June to early July. The results showed that fish larvae density is significantly positive with water discharges from the dam of Xiangjiaba and water level in this reach（P<0.05）, however, significantly negative with water transparency（P<0.01）.The increase in flow caused by upstream water during the breeding season is a key ecological hydrology index that affects fish spawning.