As we all known,lipid metabolism participate in various diseases extensively.Abnormal lipid metabolism may contribute to hepatic adipose infiltration,diabetes,atherosclerosis and so forth.Accordingly,it is urgent to find chemicals that regulate lipid metabolism.A large number of experimental studies have shown that flavonoids in fructus aurantia are the active components of lowering blood lipids.This article will describe the concept,structure and classification of flavonoids.It will also introduce the mechanism of action of flavonoids in lipid metabolism from various diseases such as atherosclerosis,hypertension and type 2 diabetes.