Abstract: 【Objective】 To analyze the fish diversity in the Dandong section of Yalu River basin in summer based on environmental DNA（eDNA）, in order to verify the feasibility of eDNA technology for monitoring fish species diversity.This study could provide technical support for dynamic monitoring of fish communities, assessment of aquatic ecological health, and conservation of fish species diversity. Additionally, it also offered fundamental information for the conservation of fish diversity in Dandong section of Yalu River basin. 【Method】 From May to August in 2022, five sampling sites were set up in the Dandong section of Yalu River basin to collect environmental samples for four times. After eDNA extraction, PCR amplification, high-throughput sequencing, and database comparison and annotation, the fish diversity in the Dandong section of Yalu River basin in summer was analyzed using R language（4.1.2）, Tableau 2019.4, PRIMER 6.0. 【Result】 A total of 67 fish species belonging to 14 orders, 30 families and 65 genera were detected at five sampling sites in the Dandong section of Yalu River basin in summer. Among them, Trachidermus fasciatus and Brachymystax lenok were listed in the List of National Key Protected Aquatic Wildlife. Eleven species, including Cyprinus carpio, Carassius auratus, Aristichthys nobilis, Hypophthalmichthys molitrix, Ctenopharyngodon idella, Liza haematocheila, Megalobrama amblycephala, Pseudosciaena polyactis, Pelteobagrus nitidus, Collichthys lucidus and Ophiocephalus argus were listed in the List of National Key Protected Economic Aquatic Animals and Plants Resources. Plecoglossus altivelis and Lampetra morii were listed in the National Endangered Animals List and the List of Key Protected Wildlife in Liaoning Province. Hucho ishikawai, Thymallus yaluensis and Salvelinus malma were listed in the Rare and Endangered Animals in Northeast China. C. carpio, C. auratus, H. molitrix, C. idellus, Abbottina liaoningensis, Opsariichthys bidens, Leuciscus waleckii, Misgurnus anguillicaudatus, Plecoglossus altivelis, Hypomesus olidus, Protosalanx hyalocranius and Cottus poecilopus had similar compositions across all sampling sites in the Dandong section of Yalu River basin, and they were dominant species with relatively high abundance, making them the dominant fish groups in the Dandong section of Yalu River basin in summer. Among the five sampling sites, Donggang site had the highest Chao1 index, Pielou index, Shannon index and Simpson index, while Dandong site had the lowest Chao1 index, Shannon index and Simpson index. 【Conclusion】 The feasibility and effectiveness of using eDNA technology to detect fish species composition and diversity in the Dandong section of Yalu River basin in summer have been demonstrated. The ecological structure of fish in the Dandong section of Yalu River Basin in summer is complex and fluctuating, with the protection of wild and rare fish germplasm resources becoming an urgent issue. Immediate actions are required to restore the rare fish resources of Yalu River, including implementing fishing bans, focusing research on artificial propagation techniques for endangered endemic fish species, and strengthening the monitoring of aquatic ecosystem health.