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. albiphloeavar. chengtuensis), Paulownia fortunei group (P. fortunei andP.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.