Abstract:The invasion of Eupatorium adenophorum in Pinus yunnanensis stand damaged by Tomicus spp. was examined. The community structure, biodiversity index and invasion extent of three P. yunnanensis stands were determined and studied, and the correlation between Tomicus spp. damage and E. adenophorum invasion was analyzed. The results indicated that the Tomicus spp. damage could cause the change of habitat through affecting the structure of P. yunnanensis community, the existence of Tomicus spp. made the plant community more susceptive to the invasion of E. adenophorum. The probability of E. adenophorum invasion enhanced under simpler community structure, lower biodiversity and less sufficient use on habitat resources. The damage of Tomicus spp. caused the stand of P. yunnanensis degraded; the invasion of E. adenophorum further speeded up the degradation of ecological system. E. adenophorum invasion has become a critical ecological process which closely related to the healthy of forest ecological system.