Pretreatment of corn cob was carried out by microwave/alkali and microwave/acid, including different power densities and time of microwave pretreatment. The results showed that average weight of reducing sugar received by microwave/alkali pretreatment was 51.71mg, over 33.82% than the control. And the weight was 8.76mg by microwave/acid. Acid/alkali pretreatments were followed by microwave treatment. Average FPA activities were 2.23U/mL and 10.90U/mL in fermentation fluid, respectively, increasing 35.05% and 17.26% compared with the control. Meantime average CMC activities were3.43 U/mL and 12.41 U/mL, respectively, decreasing 15.96% and increasing 34.32% respectively compared with the control. Alkali pretreatment of corn cob followed by microwave was better than the acid pretreatment.