To explore the relationship between the temporal and spatial characteristics of larval Ctenopharyngodon idellus and hydrological factors in the Anqing section of the lower Yangtze River, the larval C. idellus were systematically monitored from April 2018 to August 2020. A total of 272 larval C. idellus were identified using morphological and molecular biological methods, of which the three-year catch accounted for 12.30%, 34.52%, and 4.37% of the four major fish catches in China in 2018, 2019, and 2020, respectively. According to the estimation of larval fish resources, their runoffs were 3.95×108 , 5.79×108 , and 3.29×108 , for 2018, 2019, and 2020, respectively. The results of spatial and temporal characteristics analysis showed that the larvae and juveniles of C. idellus were present mainly from May to July, with peaks in May and the early part of mid-July. In 2020, the abundance of larvae and juveniles of C. idellus was the lowest because the flood was not suitable for breeding and because the main flood season was delayed. Kruskal-Wallis test showed that the abundance of larval C. idellus on the left and right banks was significantly higher than that in the middle of the river (P＜0.05, n=70). From 2018 to 2020, the spatial distribution of the overall average abundance was distributed as follows: left bank (8.99 ind/1000 m3)＞right bank (5.34 ind/1000 m3)＞middle of the river (3.53 ind/1000 m3). Pearson correlation analysis showed that the abundance of larval C. idellus was significantly positively correlated with water temperature, the daily rising rate of water level, and runoff and negatively correlated with transparency. GAM model analysis showed that the relative importance of hydrological factors was as follows: water temperature＞transparency＞daily rising rate of water level＞daily rising rate of runoff. In this study, the total deviation interpretation rate of the GAM model reached 90.8%, which accurately revealed the response relationship between the abundance of larval C. idellus and hydrological factors. This study accumulated basic data for understanding the occurrence mechanism of early C. idellus resources in the Yangtze River.