An investigation was conducted to determine spatial distribution characteristics of the monogenean parasite Dactylogyrus simplex (Bychowsky, 1936) on the gill filaments of the cyprinid freshwater fish Diptychus maculatus (Steindachner, 1866) in the Yarkand River Basin, Xinjiang, from May 2019 to June 2020 through three sampling surveys. The infection and spatial distribution characteristics of D. simplex were analyzed using statistical methods. A total of 3994 D. simplex parasites were detected in 325 D. maculatus individuals, with a total infection rate of 67.7% and an average infection abundance of 12.3±1.2. The infection rates of the left and right gills were 59.4% and 57.2%, respectively, with no significant difference in infection abundance between them (P＞0.05). For the gill slice, the average infection abundance of gill I (the gill slice closest to operculum) and gill II was significantly higher than that of gill IV (P＜0.01). With the growth of the host, the infection rate, abundance, and intensity of D. simplex first increased and then decreased, reaching the highest values at 13＜S≤18 cm body length; however, no significant difference in infection was detected among the body length groups (P＞0.05). The results indicated that D. simplex had no preference for size, left and right gill, or age of the host, but preferred to parasitize gills I and II on the gill slices. The D. simplex population exhibited an aggregated distribution gills of the host. The findings of this study provide basic data for fish parasitic disease prevention and control in the Yarkand River Basin.