Abstract: Fungus Pleurotus florida and chemical sodium hydroxide(NaOH), ammonia(NH₃), and urea(CO(NH₂)₂ were used for biological and chemical pretreatment of corn stalk, respectively. It was found that the main chemical compositions such as lignin, cellulose, and hemicellulose were degraded greatly, and the physical structure of lignocellulose matrix changed as well through both pretreatments, which contributed to the improvement of anaerobic digestion efficiency of corn stalk. The anaerobic digestion experiments showed that all biological and chemical pretreatments, except urea treatment, helped increase biogas production, whereas NaOH was found to be the best one and capable of increasing biogas production by 78.3% and 13.2% as compared to the untreated and biologically treated one, respectively. Chemical pretreatment has some advantages over biological one such as easy operation, shorter treatment time, and higher biogas production. Pretreatment with NaOH (addition of 8% of corn stalk dry matter) is recommended for large scale biogasification of corn stalk. Proper chemical pretreatment could improve biogasification efficiency of corn stalk as well as other crop stalks.