In order to improve fermentable reducing sugar yield of corn straw, corn straw lignocellulose was pretreated by expansion technology. Scanning electron microscope pictures showed that the corn straw fibre bundle was destroyed and the wrapped function of lignin was weaken, so that to improve space effect of cellulase. Infrared spectrum analysis showed that some hemicellulose and small amounts of lignin were hydrolysed. X-ray diffraction showed the crystalline degree of cellulose decreased by 12.68%, respectively. By means of further cellulose enzyme solution experiment, expansion treatment of raw material’s enzymolysis time could be reduced 16 h. Without expansion material’s reducing sugar productivity was 13.48%, and expanded material’s reducing sugar productivity was 24.91%. The results show that the expansion pretreatment technology can obviously increase the corn straw lignocellulose energy-oriented utilization efficiency. The experiment provided a basis for further research on expanded corn straw enzymolysis.