In the present work, the performances of high-solids enzymatic hydrolysis of rice straw were experimentally studied. Moreover, the heat flow and weight loss of the pre- and post-hydrolysis of rice straw were measured by the simultaneous thermogravimetric analyzer. It is found that the output and yield of reducing sugar initially increased and then reduced with an increase of supplied water, hydrolysis temperature and substrate mesh, while the cellulose content in residual substrate had an opposite trends. Furthermore, a high enzyme loading resulted in a constant saccharification efficiency of cellulose. The output and yield of the sugar, 77.7 mg/(g substrate) and 0.44 g/g, were respectively achieved under the optimal conditions of the supplied water of 1.0 ml/(g substrate), enzymolysis temperature of 50 C, rice straw of 60 mesh and the cellulase dosage of 2.0 mg/(g substrate). Simultaneous thermogravimetric analysis on the rice straw indicates that the chemical compositions of rice straw changed after enzymolysis. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.