The catalytic performance of Ni-Mo supported on Sb promoted γ- Al₂O₃ was evaluated in combined steam and carbon dioxide reforming (CSCRM) of methane. The catalyst was modified with different loading of Sb(1, 3 wt%) over Ni(12)-Mo(1)/ γ-Al₂O₃ by the impregnation. Catalysts was calcined at 750 °C, 5hr with Ar carrier gas and tested at 900 °C , 1 atm with feed ratio of CH4 : CO₂ : H₂O : Ar = 1 : 0.8 : 1.3 : 1 and WHSV = 40,000 h-1 for 8 hours. As a result, addition of Sb on Ni-Mo/ γ- Al₂O₃ had an effect on the strong resistance toward carbon formation and improved the catalytic activity. Among the catalysts investigated, the optimal catalytic activity and stability was achieved over the sample with 3 wt% of antimony.