Abstract: We conducted a general survey on 170 cultivars of Paeonia lactiflora in Yangzhou University in 2015. The diversity of 11 different phenotypic traits were recorded and analyzed. The P. lactiflora cultivars exhibited rich phenotypic diversity, with an average diversity index of 1.538. Overall, the diversity index of quantitative traits was higher than that of the qualitative traits. Principal components analysis (PCA) revealed the top five principal components, with eigenvalues higher than one. The phenotypes selected from the five principal components reflected most of the information on the 170 types of P. lactiflora. The five morphological traits with the highest contribution rates were petal width, plant height, stamen number, leaf color and stem diameter. Through cluster analysis, the average genetic distance between different varieties was about 10.0, indicating that phenotypic variation was relatively high. Plant height and peony cluster results were strongly correlated.