Abstract: A fermentation process for preparing a postbiotic with a by-product of wheat processing includes: preparation of a material; inoculation of Paenibacillus polymyxa (P. polymyxa)+Brachybacterium paraconglomeratum (B. paraconglomeratum)+Flavobacterium pectinovorum (F. pectinovorum) as fermentation strains; and isolation and extraction of the postbiotic. Since wheat starch wastewater and wheat bran include abundant nutrient components, the wheat starch wastewater and wheat bran can be used to prepare postbiotics, which is conducive to reducing a wastewater treatment cost of a related enterprise and protecting the environment, and can turn waste into treasure and increase an added value of an agricultural product.