Abstract: Ni-5, Ni-5PM were selected, by previous study, as catalyst according to their good performance upon the reaction of CH₄ to CO₂. Based on this selection, natural-gas/CO₂ is used to replace CH₄/CO₂ reaction system. the experimenntal results show that Ni-5 and Ni-5PM have a fairly high conversion activity upon natural gas/CO₂. But in reaction, the defect is the carbon formed by cracking of high hydracarbon deposits in reactor. To prevent such deposition, "carbon remover A"(CRA) is added. As it turns out that CRA effectively prevents carbon deposition in reactor while having slightly effect on synthesis yield, catalysis activity, selectivity, stability, and doesn't enter into exit gases.