Abstract: In this study, the population resources of Coreius guichenoti (C. guichenoti) at the end of Liyuan Reservoir, Ahai Reservoir, Jinanqiao Reservoir and Shuiluohe section in the middle reaches of Jinsha River were investigated in April and July of 2022 and April and June of 2023, and the fish resources of early life history stages were monitored for 30 days at the corresponding monitoring sections in June and July of 2023. The population structure, spawning site distribution and spawning scale of C. guichenoti in the middle reaches of Jinsha River were analyzed. The results showed that: ① 990 fishes and 30 species were collected in four sections from 2022 to 2023, including 112 individuals of C. guichenoti. 96 C. guichenoti individuals were collected from the end of Ahai Reservoir, accounting for 85.71% of the total number. This result indicated that the end of Ahai Reservoir was the most important distribution area of C. guichenoti. ② In the end of Ahai Reservoir, the weight of C. guichenoti individuals ranged from 108.8~511.5 g, body length ranged from 230 mm to 308 mm, age ranged from 2⁺ to 6⁺ years, and the gonadal stage ranged from Ⅰ to Ⅵ, indicating that the C. guichenoti population of this section had a complete generation. The weights mainly distributed in 200~300 g and 300~400 g. The age stages were mainly 2⁺~3⁺ years and 4⁺~5⁺ years, and the gonadal development was mainly in stage Ⅲ. In 2023, the total number of eggs of C. guichenoti at the end of Liyuan Reservoir, Ahai Reservoir and Jinanqiao Reservoir were 1.99×10⁶, 5.46×10⁶ and 1.06×10⁶, respectively, while no eggs were identified in Shuiluohe section. ③ The number of spawning eggs of C. guichenoti at the end of Ahai Reservoir and Jinanqiao Reservoir accounted for 53.69% and 79.10% of the total breeding scales in the corresponding river sections. The runoff of eggs and fries were the most abundant at the end of Ahai Reservoir, inferring this area may be the only habitat where the population was large enough to reproduce naturally. ④ Aiming at the obviously declined trend of the resources of C. guichenoti and to protect the resources of C. guichenoti at the end of Ahai Reservoir, some protection suggestions were put forward, such as strengthening the basic investigation and research on C. guichenoti, calling for ecological operation targeting at hydrological processes for the reproduction of C. guichenoti in the Liyuan and Ahai reservoirs, suspending the construction of Jieke Hydropower Station in Shuiluo River and strengthening the impact argument on Longpan Hydropower Station. The research results can provide scientific support for the protection and restoration of the C. guichenoti population.