NOVELTY - Fermentative production of fuel ethanol using yeast lees comprises drying the lees, crushing, sieving and then adding into a fermentation flask, adding water, urea, ammonium sulfate, mixing, regulating the pH to 3.5-4, sealing and sterilizing in a steam sterilizer, cooling, adding complex enzyme aqueous solution to carry out liquefaction and saccharification, cooling, adding dry yeast activation solution and sugar syrup, treating, incubating, sealing and culturing, sampling and observing under microscope, fermenting in a sterile biochemical incubator, and distilling the fermented matured mash.    USE - The method is useful for fermentative production of fuel ethanol using yeast lees (claimed).    ADVANTAGE - The slag obtained from the method is used for microbial fermentative production of biogas, organic fertilizer, mushroom cultivation and development of farming.    DETAILED DESCRIPTION - Fermentative production of fuel ethanol using yeast lees, comprises: (i) drying 480-500 g lees, crushing, sieving via 0.8-1 mm sieve, then adding into a 3 l fermentation flask, adding 1400-1500 ml water into the flask, mixing at 32-34 degrees C, adding 13-15 g urea, 10-15 g ammonium sulfate, uniform stirring, then drop-wisely adding acid to regulate the pH to 3.5-4, and sealing using three layered gauze; and (ii) sterilizing the flask in a steam sterilizer at 120-122 degrees C with a pressure of 0.1-0.105 MPa for 110-130 minutes, allowing the sterilizer to cool, taking out the flask and cooling to 48-50 degrees C, adding 1.8-2.5 wt.% complex enzyme aqueous solution (mixture of high-temperature resistant alpha -amylase, glucoamylase, cellulose and acid protease in a mass ratio of 1:1:1:0.5-1) into the flask to carry out liquefaction and saccharification for 60-65 minutes, cooling to 31-33 degrees C, adding 12-15 wt.% resurrection dry yeast activation solution (same amount of acid protease) at 35-40 degrees C, adding 2-3% reconstituted sugar syrup, treating for 15-20 minutes, reducing the temperature to 32-33 degrees C and activating for 1-2 hours, incubating the flask in a sterile cyclotron oscillator and rotating for 100 rotations/minute, sealing with two or three layered gauze and culturing for 8-10 hours, sampling and observing yeast cell number and budding rate via microscope, then placing in a sterile biochemical incubator and fermenting at 32-36 degrees C by stirring once at 4th hour, 8th hour and 12th hour, then stirring once for every 7-8 hours, where the culture reaches into middle and late fermentation after 40 hours, fermenting for 72 hours by stirring once for every 12 hours, taking out the fermented matured mash and distilling.