The influence of introduction of cyanuric chloride on glucose's yield (Y) in acid-catalyzed hydrolysis of microcrystalline cellulose (MCC) has been studied. The content of cyanuric chloride (C) in modified MCCs was determined by X-ray photoelectric spectroscopy. The chemical structures of modified MCCs were analyzed by Fourier transformation-infrared spectroscopy and cross polarization/magic angle spinning C-13 nuclear magnetic resonance. Crystal index (Cl) and the ratio (R) representing the sum of content of (1 (1) over bar0) and (1 1 0) to that of (2 0 0) were calculated based on diffraction intensity in wide angle X-ray diffraction (WAXD). Hydrolysis experiment and WAXD show that V. Cl and R vary with C. The modified MCC containing 3.9 mol% of cyanuric chloride has the highest V. the highest R and the lowest Cl. Variations of Cl and R show that the chemical modification changed the proportion of crystal/amorphous and crystal planes, both of which influence glucose's generation in hydrolysis of cellulose. (C) 2011 Elsevier Ltd. All rights reserved.