Abstract: In order to investigate the fauna and diversity of small mammals in Sichuan Xiaozhaizigou National Nature Reserve, a survey was conducted by snap traps and pitfall traps in May and August, 2018. The results showed that there were 20 species of small mammals belonging to 12 genera, 5 families and 3 orders. Neotetracus sinensis, Ochotona huanglongensis, Episoriculus caudatus and E. macrurus were first reported in this reserve, Uropsilus soricipes should be a cryptic species.Meanwhile, a very rare species, Chodsigoa smithii, was discovered. The above-mentioned intermediate-altitude area was worth being pretected for small mammals.