The invention discloses a method for preparing ethanol from a cellulose-containing raw material, which comprises the following steps: in the presence of water, mixing a cellulose-containing raw material with enzyme, carrying out enzymolysis to obtain an enzymolysis product, and fermenting the enzymolysis product. The enzymolysis is characterized by comprising a main enzymolysis stage and an intermitted enzymolysis stage after the main enzymolysis stage which are continuously performed, wherein in the main enzymolysis stage, proper amounts of the cellulose-containing raw material and enzyme are continuously added into an enzymolysis tank so that the monosaccharide content in the enzymolysis product in the main enzymolysis stage is 50-100 g/L, and the enzymolysis product of the main enzymolysis stage sequentially and continuously flows into the enzymolysis tank of the subsequent stage to perform enzymolysis until the monosaccharide content in the enzymolysis product at the enzymolysis end point is greater than or equal to 105 g/L. The method effectively enhances the saccharide conversion rate and enzymolysis efficiency of the raw material, and therefore, greatly enhances the yield of ethanol and shortens the production cycle.