NOVELTY - Preparing ethanol fuel by extracting pectin and hesperidin from a feedstock containing orange peel residue, involves adding first residue of cellulite and buffer solution to batch reactor, adjusting pH, then adding cellulase and performing enzymolysis reaction at constant temperature, and after hydrolysis, performing solid-liquid separation to give solid residue and sugar solution; mixing sugar solution, peptone, yeast extract, ammonium sulfate, magnesium sulfate and potassium dihydrogen phosphate, adding cellulite and yeast into fermenter, stirring to obtain ethanol fermentation liquid.    USE - For preparing ethanol fuel (claimed) which is used in energy power fuel and chemical production.    ADVANTAGE - The method provides high ethanol yield using simple production device; has low operation cost; is environment-friendly; is easy to popularize for industrial production; has high economic value in industry.    DETAILED DESCRIPTION - Preparing ethanol fuel by extracting pectin and hesperidin from the feedstock containing orange peel residue, involves: (i) taking residue of cellulite on dry basis in accordance with mass: cellulase in accordance with mass: citric acid-sodium citrate buffer solution in accordance with volume at ratio of 1 g:(10-70) mg:(10-50) ml, sequentially adding first residue of cellulite and buffer solution to a batch reactor, and then adjusting the pH of the solution in batch reactor at 4.5-6 using solution of high concentration of hydrochloric acid or sodium hydroxide, followed by the addition of cellulase and performing enzymolysis reaction at constant temperature of 30-60 degrees C and at rotation speed of 80-200 revolutions per minute (rpm) for 48-72 hours, obtaining the mixture after the hydrolysis, and then placing in a filter press, and performing solid-liquid separation to obtain a solid residue and restores sugar; and (ii) after completing the step, adjusting the pH of the obtained sugar solution at 4-5.5 using high concentration of hydrochloric acid or sodium hydroxide solution, and then mixing sugar solution: peptone: yeast extract: ammonium sulfate: magnesium sulfate: potassium dihydrogen phosphate in a ratio of 1 liter: (10-25) g: (1-10) g: (1.5-3.5) g: (0.2-0.8) g: (3-7.5) g, and then taking dry residue of cellulite: dry yeast in a mass ratio of 1000 g:(1-15) g, and sequentially adding to the fermenter at constant temperature of 20-35 degrees C and at rotating speed of 80-200 rpm, stirring to ferment for 24-60 h to obtain ethanol fermentation liquid.