Abstract: This paper present a species of extraneous weed that is native tO the Andes of the south America. Now, it has become the wide distribution in low altitude region of the southern Yunnan. According to data and investigation, we know that Eupatorium odoratum has extended from thailand through Burma to the southern Yunnan since 1930. Moreover, in these areas it can be set foot, the wide-spread, naturalized, and often formed a secondary consociation, has directly connection with temperature.

Key words: primary, eupatorium, odoratum, community, Yunnan