Trachypithecus francoisi is one of the most precious and rare primates in the world. It is significant for the conservation of endangered species to study the gut microbial community structure of T. francoisi in different habitats and their functions on host energy metabolism, nutritional balance and food digestion. Metagenomic sequencing technology was used to compare and analyze the gut microbial community composition and function differences of wild(five individuals) and captive(four individuals) monkeys in this study. The results showed that in terms of species composition, the gut core microbiota of T. francoisi was mainly Firmicutes and Bacteroidetes, Methanobacteriota showed the most significant difference. There was no significant difference in gut microbial diversity and uniformity between wild and captive monkeys (P >0.05). Functionally, most of the genes in the intestinal microbial community of T. francoisi was related to metabolism and genetic Information, and there were significant differences between wild and captive T. francoisi in amino acyl TRNA biosynthesis, pyrimidine metabolism, propionic acid metabolism pathways (P <0.05). Ruminococcus and Blautia increases the ability of T. francoisi to produce Acetyl-CoA in captivity by regulating FOX2 gene expression. This study initially revealed the effects of the wild environment and captive environment on the characteristics and functions of the gut microbial community of T. francoisi in Guizhou Province, which is helpful for scientific assessment of the physiological health status of the wild population of black langur monkeys, and provides theoretical basis for the gut microbiology of this rare species in the wild population protection and captive population breeding.