The present invention relates to a method for preparing a whole soybean milk with superior storage stability which shows almost no change in viscosity when stored for a long time, and a whole soybean milk prepared thereby. As a method of the present invention provides a whole soybean milk having small particle sizes based on a procedure simpler than pre-existing methods, time for preparing a whole soybean milk can be shortened. Further, as the whole soybean milk obtained by this method shows almost no change in viscosity when stored for a long time, its shelf life can be extended dramatically as compared to pre-existing whole soybean milk containing both soybean milk residue and soybean liquid, which shows viscosity increase over time.
