Abstract: Xishuangbanna District is one of the three areas where have tropical rain forests in China.In this paper,endemic species,predominant species,species diversity index,evenness index,predominant index,and similarity coefficient of ants in 16 subtypes of vegetation in Xishuangbanna District are studied.220 species belonging to 8 subfamilies and 66 genera were collected.The maximum of species diversity index is observed in the seasonal rain forest in rainy season,that is 2.908;while the minimum of species diversity index is found in the tea garden in dry season,that is 0.114.For the composition of ant species,mountain rain forest and monsoon evergreen broad-leaf forest have the greatest similarity coefficient,that is 0.356;while warm deciduous broad-leaf forest and tea garden have the smallest similarity coefficient,that is 0.017.Each subtype of vegetation has its endemic species.Among them,semi-evergreen monsoon forest is richest in endemic species,reaching to 13 endemic species.In contrast,hill land shrub is poorest in endemic species,with only 1 endemic species.Seasonal rain forest and semi-evergreen monsoon forest are richest in rare species,so these two subtypes of vegetation are most valuable for conservation.Karst monsoon forest,monsoon evergreen broad-leaf forest,mossy evergreen broad-leaf forest,warm deciduous broad-leaf forest,and warm pine forest also have their own rare species,these subtypes of vegetation also have important value for conservation.Predominant species and their percentage in the 16 subtypes of vegetation in dry and rainy seasons are different from one to another.The most common predominant species in dry season is Pseudolasius silvestrii Wheeler.While in rainy season,P.silvestrii Wheeler and Pheidologeton diversus (Jerdon) are the most common predominant ones.