Abstract:Abstract Plants of Loranthaceae did selectively harm io some plants, specially to partial trees and shrubs of dicotyledon in Xishuangbanna, Yunnan. Liana of dicotyledons and plants of gymnosperms were harmed little. Harmed ferns and monocotyledons have not been found. The harm of Loranthaceae is closely related to their adaptations to trees and environments, their biological features and natural regeneration abilities.