The invention belongs to the technical field of deep processing of soybean byproducts, and discloses a method for combinedly extracting a soybean fiber and a bean dreg protein by a homogenization assisted alkaline process. The method comprises the following steps: after screening bean dregs, dispersing the bean dregs in de-ionized water, after homogenizing a solution for 1 to 3 times at 300 to 600 bars, adjusting pH to 9.0 to 13.0, and then stirring and performing ultra-filtration to obtain filter residue and filtrate; redissolving the filter residue in de-ionized water, adjusting pH to a neutral value, and drying to obtain the soybean fiber; adjusting the pH of the filtrate to 3.0 to 5.0, after standing at room temperature, centrifuging, redissolving obtained precipitate in de-ionized water, adjusting the pH to a neutral value, and drying to obtain the bean dreg protein. Two main substances in the bean dreg are extracted at the same time, so that the limitation that only one substance in the bean dreg can be extracted is broken through, and the additional value of bean dreg byproducts is greatly improved. The extracted soybean fiber is strong in water-holding/oil-holding ability and good in expansibility, and the extracted bean dreg protein has the advantages such as strong water-holding/oil-holding ability.