The aim of this study was to improve the yields of sugar with enzymatic hydrolysis on 2% sulfuric acid pretreated corn straw using pectinase

β

-glucosidase and cellulase. The results showed that the yields of glucose

xylose

and enzyme hydrolysis were 67.83%

3.25%

and 73.65%

respectively

when the pretreated corn straw was hydrolyzed using pectinase

β

-glucosidase

and cellulase were 45U/mL

30U/mL and 60U/mL for a period of 48 h. Compared with single cellulose enzymatic hydrolysis

the yields of glucose

xylose and enzymatic hydrolysis with compound enzymes increased to 65.04%

20.82%

and 65.06%. The yields of ethanol with compound enzymes increased to 72.5% in the step by step fermentation for 5 days. These results suggest that the mixture of three kind of enzyme can obviously increase the yield of sugar with enzymatic hydrolysis. The research results provide an important reference for the research of corn straw into fermentable sugar technology.