Abstract: From May 2017 to September 2019, the diversity of large and medium-sized animals in the Jiudingshan Nature Reserve in Sichuan province was monitored by infrared camera technology. In this study, with an intensive survey effort of 7457 efficient camera days at 49 locations (26 grids), a total of 7339 photographs and videos of wild mammals were captured, among them 7231 photographs and videos of specific species of mammals were accurately identified and 1190 independent records were recorded. A total of 18 wild mammal species belonging to 11 families and 4 orders were identified, while the remaining mammals that could not be accurately identified were recorded as Muridaes, Sciuridaes and Mustelidaes. Among the 18 wild mammals, Carnivoras (7 species, 4 families) were the highest in species richness, followed by Artiodactyla (6 species, 4 families) and Rodentia (3 species, 2 families). From independent and effective records, Artiodactylas were with the greatest number of detections (67.14%), followed by Primates (17.14%) and Carnivora (10.09%), and all the three taxa were up to 94.37% of all detections. Four species were listed as Class I national key protected wild animals in China and five species as Class II. One mammal species was evaluated as Endangered (EN) by IUCN Red List, 3 species evaluated as Near Threatened (NT) and 5 species evaluated as Vulnerable (VU). Based on the relative abundance index (RAI), Chinese Goral (Naemorhedus griseus) (6.91), Tufted Deer (Elaphodus cephalophus) (2.27), Tibetan Macaque (Macaca thibetana) (1.77), Golden Snub-nosed Monkey (Rhinopithecus roxellana) (0.98) and Sichuan Takin (Budorcas tibetanus) (0.80) were ranked as the top most 5 abundant mammal species. This survey had obtained valuable infrared images data of wild animals and distribution information of some mammal species in Jiudingshan Nature Reserve, accumulating basic data for follow-up continuous monitoring work for further updating, revision and improvement of the species list in the reserve.