Abstract: To deal with the short of energy sources and look for the best way to use the crop straw, the method of hydrolysis under dilute acids is used to hydrolyze straw cellulose. The experiment is based on self-devised dilute acid hydrolysis device and takes corn straw as the raw material. The orthogonal test was used to optimize 4 factors, namely H2SO4 concentration, corn stover granularity, the melt salt catalyst species and concentration. The yield of oligosaccharide was used the index in the orthogonal test. The results showed that the chromium chloride、the ferrous chloride、the copper chloride and the zinc chloride could improve the efficiency, and also concluded the best arrange in pairs or groups under different catalyst. The best reducing sugar yield was received with 2% sulfur acid, 60 mush and 1% ferrous chloride. The results are good for application.