Objective：To study degradation kinetics of bergenin in the SFE-CO2 extraction of Bergenia Purpurascens. Methods:To find the law of degradation, the contents of bergenin were tested by UV-visible spectrophotometer under storage, drying and light irradiation conditions. Results：The rate of degradation of the SFE-CO2 extraction of Bergenia Purpurascens was 1846% within 20 days when kept away from light. The degradation reaction was the zero-order under light irradiation, the reaction-rate constant was 1 9mg·g-1·h-1and the half life was 307d. When drying, the concentration of bergenin increased within 12 hours and then decreased. The degradation reaction was the zero-order at 60℃, 70℃, 80℃, 90℃, 100℃ and the activation energy was 18 7kJ·mol-1. Conclusion：The SFE-CO2 extraction of Bergenia Purpurascens should be dried under lower temperature, sealed and kept away from light when storage.