Abstract: In order to explore Xylotrchus rusticus L. associated fugal community composition and pathogenicity, dilution plate method was used to isolate fungi from X. rusticus L. instar, host frass that nine kinds of materials, and there were 72 strains which belonged to 19 genera. After X. rusticus bore into the host poplar, fungi could cause significant changes within the host community bark and xylem sap. Compared with healthy poplar, X. rusticus and fungi within the bore path composition and dominant strains types were significantly different. Our study showed that Fusarrium solani (Mart.)Sacc was Xylotechus beetle larvae, paupae and termite damage its dominant bacteria presented on the surface of bark. The dominant bacteria culture medium for hydroponic poplar branches had pathogenic, and with prolonged duration of action which enhanced pathogencity.