Abstract: The hypeilipidemia- regulating and anti- atherosclerosis effects of α- amylase inhibitor ( α- AI) that purified from white bean was studied.Through the establishment of hyperlipidemia model, the TC, TG, HDL- C, LDL- C, AI values in rat serum and TC, TG levels in liver and body fat ratio of rat fed α- AI with low, medium and high dose ( α-AI: 50, 100, 150 mg /kg) were determined in the first 28 d, while the effect on liver lesions in rats was also examined.Results showed that the α- AI could significantly reduce the concentration of TC, TG, LDL- C in serum as well as TC, TG in liver and significantly reduced atherosclerosis index ( AI) , the concent of liver fat and body fat ratio, while increasing HDL- C levels in hyperlipidemic rats, which had a dose- dependent manner that the higher content of α- AI the effect was more obvious. The α- AI had significant lipid- lowering effect and prevention of hyperlipidemia and atherosclerosis formation.