Abstract: The antioxidant stability of flavonoids from Scutellaria baicalensis Georgi was assessed by its capacity to scavenge the DPPH free radical under different treatments ( such as pH, temperature, illumination, and metal ions) . Results indicated that the scavenging capacity of flavonoids from S. baicalensis against DPPH free radical decreased with the increase of pH or extension of illumination, while temperature or metal ions did not produce a great reduction of scavenging capacity.The paper preliminarily analyzed the antioxidant stability of flavonoids from S.baicalensis to provide the underlying data for future development as natural antioxidants.