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[Objective] The present paper aimed to study the genetic diversity and population structure of different geographical populations of Triplophysa lixianensi in Lixian county, and to further utilize the genetic germplasm resources of T. lixianensi in Lixian county so as to protect its wild population, the population structure of T. lixianensi in the Yangtze River Basin was investigated in the present study. [ Method] In the study, length composition, body weight composition, length-weight relationships and genetic structure variation of 117 T. lixianensis in four regions of Dadu River were analyzed, and the genetic diversity analysis was performed using D-loop control region of mitochondrial DNA. [Result] The regression equation of body weight and body length was y = 0. 0123x2.9734. The b value was 2. 9734 which was close to 3, indicating that the current growth state was acceptable. A total of 32 variable sites and 28 haplotypes were identified in 878 base pairs of 117 individuals. There was no shared haplotypes among the individuals from four regions. The haplotype diversity of four populations ranged from 0. 637 to 0. 921, and the nucleotide polymorphisms of four populations ranged from 0. 000 91 to 0. 005 70. There was no genetic differentiation between Jinchuan population and Danba population, Luding population and Shimen population, but there was significant genetic differentiation between Luding population and Jinchuan population or Danba population, and between Shimian population and Jinchuan population or Danba population. By constructing the NJ tree, we found that 117 individuals of T. lixianensis formed two independent branches in the evolutionary tree, which was consistent with the genetic distance results of each geographical population. [Conclusion] We suggest that Jinchuan and Danba populations of Dadu River should be managed and protected as a whole protection unit, and that Shimian and Luding populations should also be managed and protected as a whole, while Jinchuan and Danba populations, Shimian and Luding populations should be managed and protected separately. [ABSTRACT FROM AUTHOR]