Abstract: Effects of ionic liquid volume，sulfuric acid amount，microwave irradiation time，microwave irradiation temperature，microwave irradiation power on dilute acid hydrolyzed saccharification of corn straw in ionic liquid ［Bmim］Br by microwave irradiation were investigated.Results indicated that the best conditions of acid hydrolysis were as follows：sulfuric acid amount 100%，ionic liquid volume 100 mL，microwave irradiation power 600 W，microwave irradiation temperature 85℃，microwave irradiation time 60 min，and the yield ratio of reducing sugar could reach 2246% obviously higher than yield ratio of reducing sugar not only by traditional dilute acid hydrolysis but also by microwave irradiation heating in ［Amim］Cl or ［Bmim］Cl ionic liquid.