Gasification experiments on bituminous coal at different air/coal ratios were carried out using a newly designed combined dual-fluidized-bed pyrolysis/gasification (CDBPG) system. The effect of the air/coal ratio on temperature profiles, gas composition, gas heat value, tar yield, carbon conversion, and cold gas efficiency were demonstrated in this study. In the CDBPG system, only mixing the pyrolysis gas and the gasification gas to produce fuel gas is more efficient than single-bed gasification. Tar cracking was favored by an increase in the air/coal ratio of up to 2.4 m(3)/kg, and this is beneficial to improve the fuel gas value. The heat value of the product gas and the cold gas efficiency were maximized at an air/coal ratio of 2.1 m(3)/kg.