Current cellulosic ethanol production is hindered by the high processing costs, capital investment, and relatively low sugar yields. Efficient conversion of biomass to sugars is the last obstacle to emerging cellulosic ethanol industries. Common reed is a very aggressive, robust, and densely growing grass that is posting ecological threat by crowding out native plants. Common reed has a very high biomass productivity per acre per year. Utilization of common reed as a bioenergy feedstock will bring 2-fold benefits, a control over this invasive plant and an increase in energy security. A new cellulose-solvent-based lignocellulose fractionation (CSLF) technology has been developed for isolating lignocellulose components based on their different solubilities in different solvents (Zhang et al. Biotechnol. Bioeng. 2007. 97: 214). The optimal pretreatment conditions for common reed were found to be 84% H₃PO₄ at 50^oC for 60 minutes. To reduce enzyme utilization, we further investigated to decrease the enzyme loading from 15 FPU of cellulase per gram of glucan to lower levels without significant reduction in sugar yields. Scanning electron microscopy (SEM) images clearly show that CSLF can completely destruct fibril structure of common reed, resulting in a drastic increase in cellulose accessibility to cellulase.