The reforming of CH4 reaction with CO2 was studied over supported catalysts. From this study, we have recognized that the catalytic behavior of the copper catalysts were affected by many factors such as the reaction temperature, the categories of precursors of active metals, the additives, and the supports of the catalysts. In this study, it was found that the catalysts having carbon depositions not only performed higher activities but also became more stable. TPO results have shown that three types of carbonaceous species, C£\, C£] and C£^, were found to exist on the supported copper catalyst during CH4-CO2 reforming reaction. The mechanism of the carbon deposition was also investigated, and we propose a model to explain this process. The effects of various additives on the performance of the catalysts were also explored. We found that the Cu/Ni/SiO2 bimetallic catalysts exhibited high activities regardless of the ratio of Cu/Ni. These catalysts exhibited higher activity and stability than the monometallic catalyst at 800¢J. The deactivation rates of these catalysts were only about 0.15- 0.31% h-1 (after more than 20 hours on stream). Therefore, the Cu/Ni/SiO2 bimetallic catalysts are preferable for the carbon dioxide reforming of methane.