Hydrogen production by biomass gasification in supercritical water (SCW) is a promising technology for utilizing high moisture content biomass, but reactor plugging is a critical problem for biomass gasification in the tubular reactor. A novel SCW fluidized bed system for biomass gasification was developed successfully in State Key Laboratory of Multiphase Flow in Power Engineering (SKLMF) to prevent the plugging and it was designed for the temperature up to 923 K and the pressure up to 30 MPa. Model compound (glucose) and real biomass (corn cob) were gasified under SCW conditions to generate hydrogen-rich fuel gas and a performance testing of the new SCW fluidized bed system was conducted. The product gas composed of H(2), CH(4), CO(2), Co and small amount of C(2)H(4) and C(2)H(6) was obtained. The effects of solution concentration, temperature, pressure and oxidant concentration on gasification were studied. 30 wt% glucose and 18 wt% corn cob feedstocks were continually and stably gasified and reactor plugging was not observed. The results showed that using fluidized bed reactor for biomass gasification in SCW has many advantages and good prospects. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.