Series nickel catalysts Ni/MgOx/CaO1-x (x = 0.3, 0.5, 0.7, Ni: 5 wt%) were prepared and tested in fixed-bed reactor for biomass tar steam reforming, toluene as tar destruction model compound. Different ratios of MgO and CaO were mixed to simulate dolomite as Ni support. Two preparation methods: solid mixing with (SMW) and without water (SM) were used, the preparation methods and concentration of MgO had an important influence on toluene conversion and products. Catalysts prepared by SM method exhibited higher performance on toluene conversion, resulted in higher H-2 yield, and also, higher CO2 and lower CO selectivity with higher temperature. For the same preparation method, higher concentration of MgO resulted in higher toluene conversion, and also influence on CO, CO2 selectivity, but no obvious influence on the H-2 yield. Catalysts were characterized by BET, X-ray diffraction (XRD), SEM. (C) 2009 Elsevier Ltd. All rights reserved.