Abstract: In order to utilize the lignocellulose in waste distiller’s grains ( WDG) effectively, the effect of mixed acid concentration, hydrolysis time and temperature on acid hydrolysis efficiency of WDG were investigated by means of orthogonal test. The concentration of xylose and reducing sugar was used as evaluation index to identify the optimizing process conditions of acid hydrolysis.The optimum pretreatment conditions of WDG was also analyzed. The results showed that the ultrasonic pretreatment effects of WDG was better in the conditions of 10min, ultrasonic power of 500W at normal temperature. The optimum conditions of mixed acid hydrolysis were as follows:acid concentration 2.5% , hydrolysis temperature 120℃, hydrolysis time 2.5h.Under the above mentioned conditions, the highest productivity of xylose and reducing sugar was 651.62μg /mL and 11.85mg /mL respectively. This study provided an simple method on the comprehensive utilization of WDG.