Peony is a medicinal herb which have utilized widely as chineses medicine. The paeoniflorin is the predominant component In peony root, monoterpene glucoside containing pinane structure. The effective components were extracted with the cold water from the intact peony roots, and effectively extracted with 70% ethanol from the dry powder of peony roots. The changes of paeoniflorin contents were investigated during the drying process of peony roots and processing of peony extract by the heat-treatment. Air-drying was the best condition for the preservation of paeoniflorin content among the drying processes of peony roots. But convective drying at 6$0^{circ}C$ was recommended for the drying process of peony roots in large scale. The paeoniflorin in peony extracts was not destroyed by the treatment at 6$0^{circ}C$ and 8$0^{circ}C$ for 5 hrs, but destroyed 30%, 28% and 40% of paeoniflorin by treatment at 10$0^{circ}C$ for 5 hrs, 115$^{circ}C$ and 121$^{circ}C$ for 10 minutes, respectively. The paeoniflorin was continueously extracted for 4 hrs from the dry pieces of peony roots(0.5$ imes$0.5$ imes$0.5cm) in boiling water but destroyed gradually after 4 hrs at 10$0^{circ}C$. Paeoniflorins in 70% ethanol extracts of peony root were not destroyed at all in the process of concentration to dry powder at 60"C on vacuum.cuum.