This paper presents the experimental results of CaO sorption enhanced anaerobic gasification of biomass in a self-design bubbling fluidized bed reactor, aiming to investigate the influences of operation variables such as CaO to carbon mole ratio (CaO/C), H(2)O to carbon mole ratio (H(2)O/C) and reaction temperature (T) on hydrogen (H(2)) production. Results showed that, over the ranges examined in this study (CaO/C: 0-2; H(2)O/C: 1.2-2.18, T: 489-740 degrees C), the increase of CaO/C, H(2)O/C and T were all favorable for promoting the H(2) production. The investigated operation variables presented different influences on the H(2) production under fluidized bed conditions from those obtained in thermodynamic equilibrium analysis or fixed bed experiments. The comparison with previous studies on fluidized bed biomass gasification reveals that this method has the advantage of being capable to produce a syngas with high H(2) concentration and low CO(2) concentration. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.