Abstract: Cardiovascular disease is the chronic disease with the most deaths in our country. And natto products, made from soybean by fermented by Bacillus subtilis, have high-efficiency thrombolytic, lipid-lowering, and blood pressure-lowering effects. However, the inherent undesirable flavor of natto restricts its development in the Chinese food industry. This article mainly reviews the flavor improvement methods of natto in recent years, in theaspects of strain, technology and seasoning, and summarizes the undesirable flavor substances in natto, involving in free ammonia, pyrazine and branched-chain short fatty acids. This review aims to provide scientific basis for promoting the development of natto with good quality and flavor.