Abstract: The study aims to solve problems of late flowering and low grain state in introduction cultivation of Paeonia suffruticosa‘Fengdan’. Among the three-year-old peony plant group of‘Fengdan’, classification was conducted with different plant types of differentiation and variation in population during growth period. Agronomic characters of peony plant, such as branches of stem, plant high, leaf length, leaf width, leaf staygreen, dry weight of leaf, flowering, grains state, and so on, were studied. Correlation analysis of plant high, branches and leaf length, leaf width, and leaf dry weight was conducted. An unusual phenomenon of flowering and fructification was found in the second year on a few plants with low leaf width value, more branches, and less leaf dry weight value. Statistical analysis showed that the correlation between plant high and branches, leaf dry weight was positive (correlation coefficient value,r =0.5445** and 0.4078**,P <0.01); the correlation between branches and leaf width was negative (r =-0.5135**,P <0.01), which meant that the lower the leaf width value, the more branches were; when the leaf dry weight value was high, the branches were not always more, because the correlation between leaf dry weight and branch numbers was not close (r =0.0815). It is concluded that the unusual phenomenon of flowering and fructification of the three-year-old peony plant group of‘Fengdan’ might be relative to the distribution and transportation of photosynthetic products.