Abstract: Genetic relationship among 6 species of genus Carya and species Platycarya strobilacea was analyzed by using RAPD analysis method.Twenty primers,which showed rich polymorphism,were screened out of 600 random primers,and totally 317 DNA fragments ranging from 200 to 2 800 bp were amplified,271 of these bands accounting for 85.5% were polymorphic.According to the genetic distances calculated by using UPGMA,the interspecies relationship dendrogram was constructed.It was indicated that the classification based on the genetic relationship among 6 species in genus Carya was basically consistent with the conventional classification.And the molecular evidences supported the opinion that C.dabieshanensis should be set aside as a new species,which was genetically close to C.hunanensis and C.cathayensis.