Dilute acid precipitation method, alcohol washing precipitation method, wet hot water washing method, acid leaching alcohol precipitation method and membrane separation method. The common feature of these methods is: first, the protein in the soybean meal is precipitated by a certain method (such as heating, adding alcohol), and then the soluble components in the system are separated, so as to achieve the purpose of increasing the protein content. The raw material for the production of soy protein concentrate is generally low-denatured defatted beans.