Abstract: From March 2021 to September 2021, based on infrared camera survey technology, the diversity of large and medium-sized mammals was monitored in Hehuahai National Forest Park, Sichuan Province. A total of 40 monitoring sites were set up, and a total of 5124 d were monitored. 28829 effective records were captured, 5723 effective records were identified, and 17 species of mammals belonging to 9 families and 4 orders were identified. Among them, artiodactyla had the most species （7 species）, followed by carnivora （6 species）, and primate （1 species）. Artiodactyla and carnivorous species accounted for 76.47% of the total number of monitored mammal species. Among the monitored mammal species, 11 species （3 species in class I and 8 species in class II） were listed as national key protected wild animals, among which hairy crowned deer was the species with the largest number, the highest relative index and the widest monitoring distribution range. In this investigation, the infrared camera monitoring survey was carried out for the first time since the establishment of the forest park, and some animal activity image data in the forest park were obtained, which accumulated important basic information for mastering the diversity of the forest park and carrying out follow-up research, and put forward some suggestions for the protection of the forest park.