Abstract: Bagasse is pretreated by sulphuric acid,sodium hydroxide and alkalinity with supplementary of ultrasonic ware.The effects of different concentration,solid-liquid ratio,different temperature and processing time on pretreatment are studied.With the mass fraction of the sulphuric acid 0.8%,the ratio of liquid to material (g/mL)1∶25,and the temperature 135 ℃ for 4 min,sugar content hydrolyzed by enzyme reaches 17.81% (g/g).With concentration with the mass fraction of the sodium hydroxide 9%,the ratio of liquid to material (g/mL)1∶8,and the temperature  40 ℃ for 15 min，the sugar content hydrolyzed by enzyme achieves 14.50% (g/g).Ultrasonic wave can strengthen the bagasse alkali pretreatment  and the sugar content hydrolyzed by enzyme is 18.65%(g/g).

Key words: bagasse, fuel ethanol, pretreatment