Abstract: Research on niche differentiation of species distributed in the same domain can contribute to the formulation and optimization of targeted conservation measures. This study takes three primate species, namely the Golden Snub-nosed Monkey (Rhinopithecus roxellana), the Tibetan Macaque (Macaca thibetana), and the Rhesus Macaque (Macaca mulatta), in the Tangjiahe National Nature Reserve as the research objects. The differences in spatial scale among the three were compared using the infrared camera monitoring data from 2024. The results show that: 1) The relative abundance index (RAI) and grid occupancy (GO) of the Tibetan Macaque are the highest in different seasons, followed by the Golden Snub-nosed Monkey, while the Rhesus Macaque has the lowest; 2) Under 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 are 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, are relatively lower; 3) Under different seasons, there are extremely significant differences in the distribution altitudes among these three primate species (P<0.001). Their main active altitude ranges are 1800~2200 m, 1600~2000 m, and 1200~1500 m, respectively. In contrast, there are 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 mainly inhabit habitats with a slope of 20°~40°, semi-shady slopes (northwest-facing), deciduous broad-leaved forests, and coniferous-broad-leaved mixed forests. Overall, the spatial niche differentiation of the three primates in the reserve is mainly reflected in their distribution altitudes. This study has accumulated basic data for research on the niche differentiation of sympatric primates, and can provide research support for further exploring the coexistence mechanisms of sympatric primates as well as the optimization and adjustment of subsequent targeted conservation strategies.