[Objectives] The Hubei Mulinzi National Nature Reserve (HMNNR) is an ecologically significant region with high biodiversity, located in the transition zone from the second to the third step of China’s topography. This study aims to assess the diversity and distribution of medium-to-large-sized mammals and birds in the reserve by camera trap monitoring, with a particular focus on clarifying the relationship between altitudinal gradients and biodiversity. [Methods] From September 2019 to June 2021, 30 camera traps were deployed across habitats in HMNNR. The survey covered different elevations and functional zones. Data analysis included species identification based on morphological characteristics, calculation of the relative abundance index (I_RA), and establishment of species accumulation curves (Fig. 2). The statistical methods applied in this study included species richness estimation and I_RA calculation based on camera trap efforts. [Results] A total of 1 089 independent valid photographs were obtained, recording 14 species of mammals belonging to 10 families of 4 orders and 30 species of birds belonging to 11 families of 4 orders. The dominant mammal orders were Carnivora and Cetartiodactyla, while Passeriformes and Galliformes were the most represented bird orders. Among them, 12 species were classified as second-class National Key Protected Wildlife, including Macaque (Macaca mulatta), Asiatic Black Bear (Ursus thibetanus), Red-Billed Leiothrix (Leiothrix lutea), and Hwamei (Garrulax canorus). Additionally, five species were identified as endemic to China. The most abundant mammalian species based on I_RA were Red-Hipped Squirrel (Dremomys pyrrhomerus, I_RA = 3.60), Wild Boar (Sus scrofa, I_RA = 1.57), and Tufted Deer (Elaphodus cephalophus, I_RA = 1.34). The most frequently recorded birds were Golden Pheasant (Chrysolophus pictus, I_RA = 1.49), Temminck’s Tragopan (Tragopan temminckii, I_RA = 0.36), and Red-Billed Blue Magpie (Urocissa erythroryncha, I_RA = 0.24). Species richness was the highest in the mid-elevation range (1 400 ~ 1 800 m), where the highest I_RA was recorded. The core and buffer zones exhibited greater species diversity and abundance than the experimental zone (Table 2). [Conclusion] The camera trap survey provides updated baseline data on the diversity and distribution of mammals and birds in HMNNR. The results support the mid-domain effect, highlighting the effectiveness of long-term camera trapping in biodiversity monitoring. The findings contribute to the conservation planning and management of this ecologically important reserve. Future studies should expand the survey to cover more habitats and integrate conventional field survey methods with camera trapping for a more comprehensive assessment.