Abstract: The research on niche differentiation of species distributed in the same domain can contribute to the formulation and optimization of targeted conservation measures. In this study, three primate species, namely the Golden Snub-nosed Monkey (Rhinopithecus roxellana), the Tibetan Macaque (Macaca thibetana), and the Rhesus Macaque (Macaca mulatta), in Tangjiahe National Nature Reserve were selected as the research objects, and the differences in spatial scale among them were compared using the monitoring data of infrared camera in 2024. The results showed that: (1) The relative abundance index (RAI) and grid occupancy (GO) of the Tibetan Macaque were the highest in different seasons, followed by the Golden Snub-nosed Monkey, while the Rhesus Macaque was the lowest; (2) In different seasons, both the number of overlapping distribution grids and the distribution overlap Index (DOI) between the Golden Snub-nosed Monkey and the Tibetan Macaque were the highest. In contrast, the number of overlapping distribution grids and DOI between the Golden Snub-nosed Monkey and the Rhesus Macaque, as well as between the Tibetan Macaque and the Rhesus Macaque, were relatively lower; (3) In different seasons, there were extremely significant differences in the distribution altitudes among these three primate species (P<0.001). Their main active altitude ranges were 1800~2200 m, 1600~2000 m, and 1200~1500 m, respectively. In contrast, there were no significant differences among the three species in terms of distribution slope, aspect, and vegetation type (P>0.05); (4) All the three primate species were mainly active in the habitats of semi-shady slopes (northwest-facing), deciduous broad-leaved forests, and coniferous-broad-leaved mixed forests with slopes ranging from 20° to 40°. Overall, the spatial niche differentiation of the three primates in the reserve was mainly reflected in their distribution altitude. This study has accumulated basic data for the research of niche differentiation of sympatric primates, and could provide research support for further exploring the coexistence mechanisms of sympatric primates as well as the optimization and adjustment of subsequent targeted conservation strategies.