The main objective of this study is to investigate the characteristics of woody biomass conversion to syngas using a steam allothermal gasification process. The entering steam maintained at 877 degrees C and 1000 degrees C, respectively was used as the gasifying agent. A lab scale apparatus was built to perform the gasification experiment and the produced syngas was accurately analyzed using gas chromatography. The results clearly indicate that the syngas from steam gasification contains relatively higher H-2 concentrations, and the heating values of the syngas reach 9-10 MJ/m(3). A thermodynamic equilibrium thermochemical model that accounts for the deposition of solid carbon as a function of the entering steam temperature and the steam to biomass molar ratio was developed. The model was successfully verified by experimental results. Based on the results of model, an optimal range of the steam to biomass molar ratio is recommended. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.