Abstract: Eupatorium coelestium L. is native to the southern of North America. It is a species of harmfu1 and toxic weed which has a strong capability of propagation. Sinca 1940's, it has extended from Burma to the southern Yunnacontinuosly and now widely disperses to,the higher altitude and colder regions.In these areas it often form a pupe gregarious communisty, The ecosystem is severely disturbed, and the livestock, forest natural regeneration and agriculture are damaged.

Key words: Eupatorium -coelestium adaptability