NOVELTY - Preparing bioethanol by recovering and reusing resistant cellulase of coupling surfactants of recombinant bacteria comprises (i) pretreating crushed lignocellulose, (ii) mixing the pre-treated lignocellulose and nutrient solution to obtain a mixture 1, (iii) adding cellulose in the mixture 1, adding recombinant Saccharomyces cerevisiae expression strain for fermentation, and separating solids-liquids to obtain fermentation liquor and residues, (iv) recycling cellulase, (v) conducting saccharification and fermentation, and (vi) repeating the steps (iv) and (v).    USE - The method is useful for preparing bioethanol by recovering and reusing resistant cellulase of coupling surfactants (claimed).    ADVANTAGE - The method: avoids replenishing expensive beta -glucosidase in the recovery and reuse processes of cellulase; and greatly reduces dosage and cost of cellulase for production of ethanol.    DETAILED DESCRIPTION - Preparing bioethanol by recovering and reusing resistant cellulase of coupling surfactants of recombinant bacteria comprises (i) raw material pretreatment: pretreating crushed lignocellulose, and drying at low-temperature, (ii) preparation of a mixture: mixing 2.5-10 g pre-treated lignocellulose and 50 ml nutrient solution containing Tween 80 (RTM: Polyoxyethylene sorbitan monooleate) to obtain a mixture 1; (iii) simultaneous saccharification and fermentation: placing the mixture 1 in a reactor, at 45-50 degrees C, adding cellulose in the mixture 1, then adding cellulase, which is 10-50 FPU/g of cellulose, carrying out pre-enzymatic hydrolysis for 12-24 hours, cooling to 30-37 degrees C, adding 1-5 g/l recombinant Saccharomyces cerevisiae expression strain for carrying out fermentation at 30-37 degrees C for 72-168 hours to secrete beta -glucosidase, conducting solid-liquid separation to obtain fermentation liquor and residues, (iv) cellulase recycling: adding the pre-treated lignocellulose in the fermentation liquor for adsorption at 4-25 degrees C for 60-120 minutes, and conducting solid-liquid separation to obtain liquid and solid, rectifying the liquid to obtain ethanol, mixing the solid and the residues, adding same volume of nutrient solution containing Tween 80 (RTM: Polyoxyethylene sorbitan monooleate) for mixing to obtain the mixture; (v) placing the resulting mixture in the reactor, conducting pre-enzymolysis at 45-50 degrees C for 12-24 hours, cooling to 30-37 degrees C, adding 1-5 g/l recombinant S. cerevisiae expression strain for carrying out fermentation at 30-37 degrees C for 72-168 hours to secrete beta -glucosidase, and conducting solid-liquid separation to obtain fermentation liquor and residues; and (vi) repeating the steps (iv) and (v), where the concentration of the Tween 80 (RTM: Polyoxyethylene sorbitan monooleate) in the nutrient solution is 0.5-20 g/l.