Abstract: This paper deals with protein polymorphism in 9 taxa of Paulownia plant leaves and relationship among them. The results indicated that the 9 taxa may be divided into three groups: Paulownia australis group （Paulownia australis and P. albiphloeavar. chengtuensis）, Paulownia fortunei group （P. fortunei andP.elongata f. alba） and Paulownia tomentosa group （P. tomentosa, P. fargesii, P. albiphloea, P. lamprophylla and P.elongata）based on one-and two_dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS_PAGE )of proteins in those plant leaves, which provided evidence for classification of the genus and identification of lower taxa.