Abstract: Bacillus natto is a kind of probiotic isolated from natto fermented food. Due to its strong heat resistance and acid-base stability, Bacillus natto can resist bile stress, inhibit and even kill intestinal harmful bacteria.Bacillus natto can secrete fatty acids, vitamins, polypeptides and other nutrients that are easy to digest and absorb.It has high nutritional value. What’s more, it can help animals produce antibacterial agents such as bacitracin, and secrete nattokinase. Nattokinase has a high thrombolytic effect, which brings great help to the treatment of cardiovascular and cerebrovascular diseases. With the continuous improvement of people’s living standards, the characteristics of Bacillus natto play an important role in people’s productions and life. In view of this, this paper reviews the basic situations, functions, practical applications and fermentation technologies of Bacillus natto.