In this study, the biodegradation of fractionated corn stover in solid-state fermentation by Trichoderma reesei YG3 was investigated. Fractions of miscellaneous cells (MC) and fasciculi (FC) tissue from leaf, shell or core were separated using the combined pretreatment method of carding classification after steam explosion. The highest enzyme activities including the filter paper activity, endoglucanase, exoglucanase and ${eta}$-glucosidase activities, weight loss rate of dry material and biodegradation rate were all observed in the MC tissue fraction from the leaf, which was more nutritious, while lowest activity was observed in the FC tissue fraction from the shell. The maximum filter paper activity and weight loss rate of the dry material were 4.56 and 1.89 times the minimum and the cellulose and hemicellulose biodegradation rates were 51.22 and 39.38% versus 23.85 and 26.51%, respectively. These variances maybe attributed to the heterogeneity of the component in the fractions. A higher weight loss rate corresponded to higher enzymatic activities, whereas cellulose biodegradation was not proportional to cellulase activities. Hemicellulose biodegradation was much slower than cellulose degradation. Here, we demonstrated the importance of fractionation in component biodegradation and utilization of straw.