Abstract: To monitor fish resources and biodiversity in the headwaters of Chishui River,a comprehensive investigation was conducted using both traditional catch methods and environmental DNA (eDNA) technology from 2020 to 2021.A total of 48 fish species were identified,representing 4 orders,10 families,and 41 genera.Traditional fishing methods captured 23 fish species,spanning 2 orders,5 families,and 22 genera,while eDNA technology expanded the detection to encompass 4 orders,8 families,38 genera,and 40 species.In the analysis of fish species composition,the relative importance index (IRI) highlighted Schizothorax grahami,Acrossocheilus yunnanensis,Zacco platypus,and Semilabeo prochilus as the dominant species in the river section of the reserve.The Shannon-Wiener index registered at 2.99,indicating relatively rich overall fish resources and a relatively stable community structure.The catch Margalef index (D) reached 3.31,affirming the richness of fish species in the monitoring area,with a stable composition and population structure.Further assessment revealed a catch evenness index of 0.66,indicating a uniform distribution of population structure.Notably,differences in fish resources between the main river and tributaries were observed.Based on these findings,future conservation efforts should prioritize the core protection zone of the main stream,enhancing measures for fish diversity protection.Additionally,targeted interventions to restore tributary resources should be progressively implemented to elevate the overall resource level.This study provides valuable insights into the diverse fish species,their distribution,and recommendations for effective conservation strategies in the headwaters of Chishui River.