Abstract: Medôg area is located in southwestern Tibet and lower Yarlung Zangbo River. Its transportation is extremely inconvenient. The southern altitude of this county is less than 500 metres and its highest mountain is the Nanjagbarwa Feng with the elevation of 7 782 metres. Medôg county has a very aboriginal ecosystem,very plentiful rainfall and abundant vegetation and biodiversities. Small mammals (insectivores,bats,rodents and pikas) were surveyed in 2008 and 2011. Combined with references,31 species of small mammals were confirmed, belonging to 4 orders and 7 families. Most of small mammals belonged to Oriental realm species. And the maximum of them were Himalaya-Hengduan mountain distributing type species.