Ni-based catalysts with SiO 2 , γ-Al 2 O 3 , CaO, and TiO 2 as supports and MgO-7.5% Ni/γ-Al 2 O 3 catalysts with different contents of MgO were prepared. The structure of the catalysts was characterized by powder X-ray diffraction and N 2 adsorption-desorption measurements. The performance of the catalysts in the steam reforming of rice straw biomass to syngas was evaluated. The effects of reaction conditions on the activity of the catalysts were also investigated. Ni-based catalysts supported on γ-Al 2 O 3 had higher catalytic activity than the catalysts supported on TiO 2 , CaO, and SiO 2 . The yield of H 2 reached 1071.3 ml H 2 /g biomass and the ratio of H 2 to CO was 1.4:1 over a 7.5% Ni/γ-Al 2 O 3 catalyst. Addition of MgO to the 7.5% Ni/γ-Al 2 O 3 catalyst improved its catalytic activity. The yield of H 2 reached 1194.6 ml H 2 /g biomass and the ratio of H 2 to CO was 3.9:1 over the 1.0% MgO-7.5% Ni/γ-Al 2 O 3 catalyst. MgO not only improves the steam reforming reaction of Ni-based catalysts, but can also promote the water-gas shift reaction. This method shows promise for production of H 2 -rich syngas from biomass.