CH4/CO2 dry reforming was carried out to make syn gas on the Ni/Al2O3 catalysts calcined at different temperatures. The Ni/Al2O3 (850 $^{circ}C)$ catalyst gave good activity and stability w hereas the Ni/Al2O3 $(450^{circ}C)$ catalyst showed lower activity and stability. The NiO/Al2O3 catalyst calcined at $850^{circ}C$ for 16 h (Ni/Al2O3 $(850^{circ}C))$ formed the spinel structure of nickel aluminate, which was confirmed by TPR. The carbon formation rate on the Ni/Al2O3 $(850^{circ}C)$ catalyst was very low till 20 h, and then steeply increased with reaction time without decreasing the activity for CH4 reforming. The Ni/Al2O3 $(450^{circ}C)$ catalyst showed high carbon formation rate at the initial reaction time and then, the rate nearly stopped with continuous decreasing the activity for CH4 reforming. Even though the amount of carbon deposition on the Ni/Al2O3 $(850^{circ}C)$ catalyst was higher than that on the Ni/Al2O3 $(450^{circ}C)$ catalyst, the activity for CH4ing was also high, which could be attributed to the different type of the carbon formed on the catalyst surface.