Abstract: Transpiration of some tree species planted in hot and arid valley of Jinsha River has been studied on the spot since 1993.The result shows that those species planted successfully in the area tend to water deficit during drought period,and they can be divided into two groups according to their transpiration.The transpiration intensity of Acacia is lower than that of local species and Eucalyptus and that is characteristic of Acacia through the drought.Leaf temperature is effected remarkably by transpiration intensity and species with transpiration intensity lowing in drought period tent to wither and lose more their leaves.In addition,transpiration intensity of A.mangium and E.urophylla have both negative correlation with air temperature and positive correlation with air humidity that direct the transpiration of two species were restricted,and the other species have not remarkable correlation with those factors.