Abstract: In this paper，ISSR-PCR was used to detect the genetic diversity of these peony cultivars. Nineteen good ISSR primers selected from 122 primers were used to amplify the genomic DNA of some introduced peony cultivars to study on their genetic diversity. The results showed that 188 bands were detected，of which 177 were polymorphic with the polymorphism frequency of 94.1%. Analyzing these results by POPGENE and NTSYS，it was found that the average value of effective allele number，Nei’s gene diversity and Shannon’s information index of the detected peony cultivars were 1.514，0.3085 and 0.4713，respectively，and the similarity coefficient were ranged from 0.3294 to 0.7744. The 89 tree peony cultivars could be separated into 2 groups by UPGMA（unweighted pair group method with arithmetic average）analysis. The results also provide references for the peony genetic breeding.

Key words: Paeonia suffruticosa Andr, ISSR, cluster analysis, genetic relationship