Abstract: A molecular marker SRAP(sequence-related amplified polymorphism) was used to detect DNA polymorphism among the 36 sweet potato(Ipomoea batatas)accessions from different regions.Six pairs of primers with polymorphism among 36 accessions were used to amplify the genomic DNA.A total of 112 polymorphic bands were generated,110 of them were polymorphic bands,with an average of 18 maker bands per pair of primers.The dendrogram generated by UPMGA showed the genetic relationship among 36 accessions.The genetic similarity among 36 accessions varied from 0.62 to 0.92.In the dendrogram,there was no obvious genetic diversity between Asian accessions and American accessions,indicating that there was not geographic differentiation in sweet potato.Wild relative I.trifida(6×) clustered together with other sweet potato cultivars without distinct genetic differentiation,which suggested there was high genetic coefficient between them.And there was high genetic similarity among Chinese cultivars because they clustered together.