Abstract:To study the resistance of the chemicals which are contained in the bark of Populus tomentosa Cars.To Anoplophora glabripennis Motsh,the quantity of amino acid,suger,phenolic acid and phenolic gluconside were examined in comparition with P.alba L.It has been found that some phenolic acid and phenolic gluconside are related to the insect resistance of Populus.Populin is worth being further studied for its insect resistance. Besides,the resistance of white poplar and others were discussed here.