The characteristics of biomass air-steam gasification in a fluidized bed for hydrogen-rich gas production are studied through a series of experiments. The gasifying agent, air, was supplied into the reactor from the lower part of the reactor, and steam was added into the reactor above the biomass feeding location. The effects of reactor temperature, steam-to-biomass ratio, equivalence ratio ER, and the biomass particle size on gas composition and hydrogen production are investigated. From the experimental results, it can be seen that the higher reactor temperature, the proper ER, proper steam-to-biomass ratio SIB, and smaller biomass particle size will contribute to more hydrogen production. The highest hydrogen yield, 71 g H-2/kg biomass (wet basis), was achieved at a reactor temperature of 900degreesC, ER of 0.22, and SIB of 2.70. It is shown that under proper operating parameters biomass air-steam gasification in a fluidized bed is one effective way for hydrogen-rich gas production.