TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: In the method for producing cellulosic ethanol, the cellulose raw material is agricultural waste comprising corn straws, wheat straws, broomcorn straws, rice straws, cassava straws or cotton straws, or is industrial production waste comprising furfural residue, cassava starch or cassava residue of cassava alcohol, and comprises waste paper and municipal refuse containing a cellulose component. The raw material enzymolysis unit comprises an impurity removing and crushing unit, a gas explosion treatment unit, a stirring tank, a high-temperature sterilizing unit, a heat exchanger, a centrifugal concentrating unit, an enzymolysis tank and a cooler; the enzymolysis reaction solution prepared by the stirring tank is sterilized at 80-150 degrees C, and the retention time is 5-30 minutes; the high-temperature sterilized enzymolysis reaction solution is subjected to heat exchange by the heat exchanger and is cooled to 30-55 degrees C, then is introduced into the centrifugal concentrating device, then is introduced into the enzymolysis tank so as to be treated by enzymolysis reaction, the supernatant produced by the centrifugal concentrating device is pre-heated by the material mixing water, and is returned to the stirring tank for recycling. The CO2 discharged during the fermentation process is introduced into a CO2 washing tower, the purified CO2 is fed to the gas explosion device of the raw material enzymolysis unit. The fermented ripen mash of the rectifying and dehydrating unit from the fermenting unit orderly passes through a raw material pre-heater 1 and a raw material pre-heater 2; the pre-heated mash is introduced into a rough distillation tower, the heating mediums of the raw material pre-heater 1 and the raw material pre-heater 2 are separately waste mash collected from the rough distillation tower and waste mash collected from a kettle of the rectifying tower. The liquid-solid two-phase waste mash of the waste mash treatment unit from the rectifying and dehydrating unit during the production process of the cellulosic ethanol is subjected to pre-treatment, primary whole slag anaerobic treatment, liquid-solid separation, slag mud drying treatment, secondary anaerobic treatment, air floatation, aerobic aeration and deep treatment, where the operation temperature of the primary whole slag anaerobic treatment is 50-65 degrees C, after subjecting the waste mash to primary whole slag anaerobic treatment, the digested effluent containing slag mud discharged by the primary anaerobic tank is fed into the liquid-solid separating device, and the supernatant is fed into the secondary anaerobic tank. The waste mash treatment unit comprises primary whole slag anaerobic treatment, liquid-solid separation, slag mud drying treatment, secondary anaerobic treatment and air floatation, where the secondary anaerobic effluent is fed into an aerobic tank for subjecting the effluent to aerobic aeration treatment, part of the aerobic effluent is fed into a wastewater deep treatment device so as to continuously treated, part of the effluent is returned to the raw material enzymolysis unit for serving as material mixing water, the aerobic sludge discharged by the aerobic tank is completely returned to the primary anaerobic tank.