Abstract: The enzymatic hydrolysis of corn stover under ultrasound was studied. The results showed that the rate of hydrolysis could be enhanced by ultrasound. The effects of ultrasound power, irradiation time, temperature, enzymedosage, and pH were discussed in detail. Under the condition of 20kHz, 30W power and 10min irradiation time, the optimal enzyme dosage was 20IU/g dry substrate. The optimal temperature was 50℃ and the optimal pH was 4.8. The hydrolysis yield reached 27.30% after 48h and was 48.3% higher than that without ultrasound.