A closed-loop gasification and catalytic reforming apparatus was applied for producing syngas from corn straw with upgraded syngas quality. Four nickel based catalysts at 10% and that at 5-15% loadings on gamma-Al2O3 were synthesized and tested. Effects of reforming temperature (700-900 degrees C), steam to biomass ratio (S/B, 0.5-2.5), catalyst to biomass ratio (C/B, 0.2-0.6) on the syngas quality and the carbon conversion and gasification efficiency were investigated. Incorporation of reforming reaction with 10% Ni/gamma-Al2O3 catalyst leads to the highest CO content (50.2%) and lowest CO2 content (7.5%) amongst the four tested catalysts and amongst the Ni/gamma Al2O3 catalysts at different Ni loading. The syngas was upgraded by both the decoking reaction in the pyrolytic chamber and the steam reforming and water shift reactions in the reforming chamber.