NOVELTY - Preparing fuel ethanol, involves slicing wood raw material; pre-treating wood sheets using acid; filtering product to obtain wood sheets and xylose solution; concentrating xylose thin liquid; adding Candida shehatae; fermenting the mixture; pulverizing the wood sheets to pulp; adding cellulolytic enzyme and beta -glucosidase; hydrolyzing the coarse wood pulp; centrifugally separating the mixture to obtain enzyme hydrolysis solution; concentrating the solution; adding Saccharomyces cerevisiae; and performing anaerobic fermentation.    USE - Method for preparing fuel ethanol.    ADVANTAGE - The method enables preparation of fuel ethanol using low energy consumption wood raw material. The production device is simplified, and the method saves power consumption, operation time and production cost and increases the utilization ratio of the xylan. The reclaiming rate of the xylose reaches more than 80.0%, and the yield of the cellulose enzyme hydrolysis exceeds 65.0%. The method enables highly efficient utilization and rapid ethanol fermentation of xylose and glucose, and the sugar utilization rate and ethanol yield of the fermentation of the xylose and glucose ethanol are 82.5%, 85.0%, 90.0% and 92.0%, respectively.    DETAILED DESCRIPTION - Method for preparing fuel ethanol using low energy consumption wood raw material, involves slicing wood raw material into wood sheets; pre-treating the wood sheets for 0.5-2.0 hours at 145-160 degrees C using diluted sulfuric acid (0.5-2.0 weight/weight%) in solid/liquid ratio of 1:8-15 (weight/weight); filtering the product to obtain wood sheets and xylose solution; washing the wood sheets using water, in the solid/liquid ratio of 1:5-10 (weight/weight) until the pH value is 5.0 to obtain xylose thin liquid and diluted acid pre-treated wood sheets; concentrating the xylose thin liquid to total sugar concentration of 30.0 g/l; adding 3.0 g/l of Candida shehatae after neutralizing the liquid using alkali; fermenting the mixture for 10-14 hours at ventilation of 0.2-0.5 vvm by gas fermentation technique to obtain fuel ethanol; pulverizing the pre-treated wood sheets to pulp; controlling the pulp of wood sheets at 10-15 weight/volume%; adjusting pH value of coarse wood pulp to 4.8-5.0; adding cellulolytic enzyme (20-40 FPIU/g cellulose) and beta -glucosidase (40-80 U/g cellulose); hydrolyzing the coarse wood pulp using the enzymes for 48 hours at 50 plus minus 1 degrees C under mechanically stirring; centrifugally separating the mixture to obtain enzyme hydrolysis solution; concentrating the enzyme hydrolysis solution until the concentration of glucose is greater than or equal to 120 g/l; adding 4.0 g/l Saccharomyces cerevisiae; and performing anaerobic fermentation for 16-20 hours, to obtain fuel ethanol.