This paper reported the extraction and the preliminary determination of flavonoids in 86-11 sweet potato leaves and stems of August、September、October by UV-spectrophotometry using rutin as comparison sample,The result indicated that the highest flavonoids content in sweet potato leaves of September is 9.37% and in the sweet potato burgeoning(old)stems of August is 3.07%(2.45%).At the same time,the flavonoids content in gold sweet potato leaves and burgeoning stems of October had been tested,The result showe...