[Objective] This study analyzed genetic diversity of 22 representative peony cultivars to investigate genetic differences between peony cultivars and explore excellent germplasm resources,aiming at providing scientific basis for analysis of genetic relationships between different peony cultivars and germplasm innovation.[Method] Flower color,flower type,plant height,plant width,flower diameter,leaf length,leaf width,plant type and leaf type of 22 peony cultivars were surveyed.The genetic distances between peony cultivars were calculated with Euclidean distance method.The genetic diversity of 22 peony cultivars was analyzed by UPGMA cluster analysis.[Result]Based on the overall average of total genetic distance,UPGMA cluster analysis results were classified.Thus,22 peony cultivars were divided into five categories.CategoryⅠconsisted of Yinhongqiaodui,Jizhuahong,Babaoxiang,Chongloudiancui,Congzhongxiao,Weizi,Yanlongzi and Qiejiazi;category II consisted of Huhong;category III consisted of Xiaohuhong,Baiyulan,Yingsuhong,Fengdan,Dajinfeng,Jingyu,Panzhongquguo,Qingshanguanxue,Mojianrong,Dahongyipin and Lanhuakui;category Ⅳ consisted of Haihuang;category Ⅴ consisted of Sihelian.The classification results were consistent with pedigree analysis.Peony cultivars with unknown pedigree were assigned to corresponding heterosis group.[Conclusion]The diversity analysis of morphological traits is an effective method for investigating genetic differences between different cultivars,which may lay the theoretic foundation for breeding,industrial development and application of new peony cultivars. [Objective] This study analyzed genetic diversity of 22 representative peony cultivars to investigate genetic differences between peony cultivars and explore excellent germplasm resources, aiming at providing scientific basis for analysis of genetic relationships between different peony cultivars and germplasm innovation. [Method] Flower color, flower type, plant height, plant width, flower diameter, leaf length, leaf width, plant type and leaf type of 22 peony cultivars were surveyed. The genetic distance between peony cultivars were calculated with Euclidean distance method. genetic diversity of 22 peony cultivars was analyzed by UPGMA cluster analysis. [Result] Based on the overall average of total genetic distance, UPGMA cluster analysis results were classified.Thus, 22 peony cultivars were divided into five categories. CategoryIconsisted of Yinhongqiaodui, Jizhuahong, Babaoxiang, Chongloudiancui, Congzhongxiao, Weizi, Yanlongzi and Qiejiazi; category II consisted of Huhong; category III consisted of Xiaohuhong, Baiyulan, Yingsuhong, Fengdan, Dajinfeng, Jingyu, Panzhongquguo, Qingshanguanxue, Mojianrong, Dahongyipin and Lanhuakui; category Ⅴ consisted of Sihelian.The classification results were consistent with pedigree analysis.Peony cultivars with unknown pedigree were assigned to corresponding heterosis group. [Conclusion] The diversity analysis of morphological traits is an effective method for investigating genetic differences between different cultivars, which may lay the theoretic foundation for breeding, industrial development and application of new peony cultivars.