Method for preparing natto

The invention provides a method for preparing natto, belonging to the field of food microorganism and fermentation engineering. The natto prepared by the existing natto preparation method is bitter and has stink, thus influencing the natto taste. The method for preparing natto in the invention comprises the following steps: preprocessing, soaking, cooking at high temperature, cooling, inoculating, performing primary fermentation, performing secondary fermentation after auxiliary materials are added, and performing subpackage to obtain the finished product. The beneficial effects of the preparation method lie in that the fermentation substrate types and C/N ratio can be changed in the fermentation process by performing twice fermentations and adding auxiliary materials before the secondaryfermentation, thus reducing the generation of unpleasant flavor substances, acquiring natto with different flavors, further improving the natto taste while having no influence on natto kinase activity, greatly lightening the