In this study, biomass pyrolysis process for producing H-2-rich gas is presented. The whole biomass pyrolysis process is established and simulated based on rigorous thermodynamic model, which includes pyrolysis reactor connecting one oil cracking reactor, water gas reactor and a gasifier. The simulation results are verified by the laboratory scale experimental measurements. Then, the influence of main operation parameters such as seam/biomass ratio, temperature (pyrolysis reactor, oil thermal cracking and gasifier) on the composition of fuel gas and hydrogen yield is discussed. Lastly, the optimization results are available. The results indicate that higher gas products and hydrogen yield can be obtained from the process, the H-2 yield can reach 83 g/kg biomass, the H-2 concentration can reach 55% (mol) at the optimal temperature and steam/biomass ratio. (C) 2009 Elsevier Ltd. All rights reserved.