The key process parameters of solid state enzymolysis for the generation of soluble sugar (SS) and bio-hydrogen production from corn stalk were optimized by the response surface methodology (RSM) based on a three factor-five level central composite design (CCD), respectively. The result showed that the optimal solid state enzymolysis condition from corn stalk was 47.7 degrees C, SCED of 0.054 g/g and 10.3 days for the maximum SS yield of 526 mg/g-TVS. Correspondingly, the optimal enzymolysis conditions from corn stalk appeared at 46.3 degrees C, SCED of 0.049 g/g and 7.5 days for the maximum hydrogen yield of 205.5 mL/g-TVS from the hydrolyzed substrate by the next dark fermentation. In addition, the bio-hydrogen production mechanism from corn stalk was preliminary investigated by XRD and SEM analyses. The results suggested that the solid state enzymolysis of substrate played a vital role in the effective conversion of corn stalk into bio-hydrogen by dark fermentation. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.