Under the ongoing impacts of climate change and human disturbances on global plateau ecosystems, studies on mammalian diversity and its spatial patterns in high-altitude regions remain limited. As an important ecological transition zone between the South Asian and Qinghai-Tibet plateaus, the species composition, relative abundance, and elevational and habitat distribution patterns of mammals in the Chentang valley remain unclear. This study aims to systematically reveal the spatial patterns of mammalian diversity in this region, identify key habitats, and provide scientific evidence for biodiversity conservation on the plateau. From July 2023 to November 2024, a total of 116 infrared camera traps were deployed across the Chentang valley (46.14 km²) within Qomolangma National Nature Reserve, with an interval of at least 500 m between cameras. Sampling sites covered different elevations and habitat types and were primarily located in areas with abundant animal signs, taking into account water availability, vegetation conditions, and historical monitoring data. The survey yielded data from 2,515 effective camera-trap days, revealing spatial patterns of mammalian richness and functional structure within the region. A total of 19 mammal species were recorded, among which Carnivora had the highest number of species (12 species), while Artiodactyla had the highest number of independent detections (510 records), reflecting functional complementarity between predators and herbivores. Five species are listed as national first-class protected wildlife (Moschus leucogaster, Naemorhedus goral, Panthera uncia, Panthera pardus, and Pardofelis temminckii), and ten species as national second-class protected wildlife (Pseudois nayaur, Ailurus fulgens, Lynx lynx, Pardofelis marmorata, Prionailurus bengalensis, Macaca assamensis, Vulpes vulpes, Martes flavigula, Canis lupus, and Martes foina), accounting for 78% of all recorded species, highlighting the region's crucial role as a refuge for rare and endangered species. Species richness exhibited a unimodal pattern along the elevational gradient, indicating the ecological importance of mid- and low-elevation habitats in supporting mammalian diversity. Significant differences in species richness were observed among the five habitat types (broadleaf forest, coniferous forest, mixed coniferous-broadleaf forest, shrubland, and meadow), with the highest richness found in meadows and shrublands. This study fills the long-standing gap in systematic monitoring of the region and provides a scientific foundation for plateau ecological conservation. Future studies are recommended to integrate multi-source data (e.g., remote sensing, environmental, and anthropogenic disturbance information) with functional diversity metrics to elucidate the ecological functional patterns and environmental response mechanisms of plateau mammal communities, thereby supporting more science-based regional conservation and management strategies.