Abstract: This paper describes a new species of the genus Dactylogyrus parasitizing the gills of Gymnodiptychus dybowskii (Kessler, 1874) and Diptychus maculates (Steindachner, 1866) collected from the Gongnesi section of the Yili River Valley, Xinjiang Uygur Autonomous Region. By using traditional and molecular biological methods, the newly discovered species was confirmed as a parasite of these two hosts and was found to be somewhat similar to the parasitic species Dactylogyrus driagini (Bychowsky, 1936) and Dactylogyrus longicopula (Bychowsky, 1936). Significant differences in the morphology of the copulatory complex and the opisthaptor were observed. The supporting portion of the crossover is divided into upper and lower parts. A “Y” structure of the D. driagini support is formed at the junction, while the connection of the D. longicopula support exhibited a curly structure. Regarding the shape of the opisthaptor, those of the proposed species and D. driagini and D. longicopula are composed of a pair of central hooks, seven pairs of marginal hooks and two connected bars. The inner and outer root processes of the central hooks are not obvious, and the marginal hooks are obviously distinguishable by the hook tip, the hook handle and the handle axis. There is no spiny process at the junction of the hook tip and the hook stalk, and the lobulation of the inner and outer root processes of the D. driagini central hook is very obvious; however, the differentiation of the marginal small hook is not obvious, while the lobulation of the inner and external processes of the central hook of D. longicopula is very obvious, and the inner process is much larger than the external process. There is a spiny process at the junction of the tip of the small hook and the handle of the hook. The abdominally connected bars are thick and short, the middle portion shows peak uplift, the two ends of the D. longicopula abdominally connected bars are slender, and the middle portion shows triangular uplift. Based on the sequence alignment analysis of Dactylogyrus 18S-ITS1-5.8S rDNA, the similarity to the cryptic species Dactylogyrus cryptomeres (Bychowsky, 1934) is highest, at 92.0% similarity. The phylogenetic tree also showed that the species clusters with D. cryptomeres with a confidence of 100 (BI/ML), but taking its morphological characteristics, host habitat and host specificity, this species is not the cryptic species D. cryptomeres. Based on the results of morphological structural analysis and molecular phylogeny, the identified Dactylogyrus parasite can be considered a new species, which is designated Dactylogyrus diptychus n. sp. according to the host characteristics.