Abstract: 267 species belonging to 76 genera and 9 subfamilies of Formicidae are identified in the tropical rain forest of Xishuangbanna.The ant fauna of Xishuangbanna District is predominant in Oriental components distributed from tropics to subtropics.At genus level,the fauna is the closest to Indo-Australian,closer to Australasian,moderately related to Afrotropical and Malagasy,the farthest to Nearctic,Neotropical,and Palaearctic.It is obvious that the ant fauna of Xishuangbanna has a typical character of Asia Tropics origin,meantime it has certain origin relationship with Australia Tropics and Africa Tropics.At species level,the fauna of Xishuangbanna is predominant in Oriental ones,the closest to Indo-Australian,closer to Australasian,farther to Palaearctic,and the farthest to Neotropical and Malagasy regions.The ant fauna of Xishuangbanna has its own characters,it is the closest to that of India and Burma,farther to that of Indo-China Peninsula;close to the fauna of Southern China,but farther to the fauna of Southwestern and Central China;meanwhile the fauna includes a considerable number of endemic species.