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 on the cellulose-containing raw material to obtain an enzymolysis product, and fermenting the enzymolysis product. The enzymolysis comprises 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 products of the main enzymolysis stage respectively and continuously flow into enzymolysis tanks of the subsequent stage to perform intermitted enzymolysis until the monosaccharide content in the enzymolysis products in the enzymolysis tanks in the subsequent stage at the enzymolysis end point is greater than or equal to 105 g/L. The method can effectively enhance the saccharide conversion rate of the raw material, and therefore, greatly enhances the yield of ethanol.