First, modeling of the carbon dioxide reforming reaction(CO2RR) mechanism was carried out by the chemical affinity values of the individual elementary reactions which would be involved in the overall reaction. The chemical affinity values were obtained from a composition of an outlet stream passed through a catalyst bed. The catalysts used were Ni, Ru, Rh, Pd and Pt supported on MgO. As a result, the decomposition of CH4 to give carbonaceous deposits and H-2 was the slowest step in CO2RR. Then, a separate production of H-2 and CO over Ni catalysts from an alternate stream of CH4 and CO2 was proved by the use of a flow system equipped with two reactors in parallel, two selector valves, and two gas reservoirs. As a result, such mixtures were obtained as H-2(74%)+CH4(18%) and CO(71%)+CO2(17%) when Ni/alpha-Al2O3 was used as a catalyst.