Abstract: Paeonia cultivars were flower color phenotyped by chromatic aberration meter using 38 tree peony and 14 herbaceous peony species as test materials,the quantity classification of Paeonia cultivars were investigated,in order to provide a theoretical basis for identification,classification and flower color breeding of Paeonia.The results showed that the results obtained by cluster analysis could not scientifically characterize the classification characteristics of tree peony and herbaceous peony flowers.The ISCC-NBS color name notation defines the color more accurately.The tree peony cultivars were classified into nine groups,including yellow group,white group,green group,light pink group,pink purple group,pink red group,red group,red purple group and red black group;the herbaceous peony cultivars were classified into five groups,including white group,light pink group,pink red group,red group and red black group.What′s more,the flower color of the Paeonia cultivars was various and exists obvious difference among different cultivar groups.