The present invention relates to a legume processing method, comprising the steps of: (a) washing beans; (b) cooking the washed beans; (c) crushing the cooked beans; (d) holding the crushed beans in step (c) for a predetermined period of time; and (e) pulverizing the beans in step (d) to obtain a bean product containing single bean cells, wherein steps (b)-(c) are carried out in the same tank. The bean processing method disclosed does not require the use of any enzyme or chemical reagent. The present invention further provides a method for making whole bean soymilk, which can further process the whole bean soymilk into liquid or powder soybean products.