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 .