Currently, under huge pressure from energy demands and environmental problems, much attention is being paid to biomass conversion, which will play an important role in meeting the requirements for a sustainable society. As the most abundant biomass on earth, cellulose is usually used as the first research target for biomass conversion. In this review, the recalcitrant structure of cellulose is discussed and non-catalytic hydrolysis by hot-compressed water and catalytic hydrolysis using solid acids are then considered. We also review the catalytic conversion of cellulose into valuable chemicals including hexitols (sorbitol and mannitol), ethylene glycol, and related compounds using various heterogeneous catalysts.