Flavonoids are found in nature in a large class of plants.The extraction methods are mainly microwave,ultrasound,enzymatic hydrolysis,extraction and supercritical extraction,etc.In their separation,determination and identification,the silica gel column is used for separation,the color method is used for qualitative detection,and the HPLC and UV detection is used for quantitative.Determination of the activity of flavonoids is their antioxidant properties measured.