Alkaline metals were added in some nickel-based catalysts to improve the performance of electrode catalysts for a molten carbonate fuel cell (MCFC) reactor. Carbon dioxide reforming with methane, nickel surface measurement, TG for carbonaceous deposition and SEM-EDX for surface morphology were done by varying the kinds and amounts of alkaline metals. In carbon dioxide reforming, the addition of alkaline metals caused deactivation, except for lithium. The catalyst in an MCFC reactor was affected by lithium or potassium which was transferred from the molten carbonate salt. Therefore, it was necessary to prevent the catalyst from contacting with potassium. Lithium-added catalyst with the mole ratio (Li/Ni)=1.0 was selected and applied to the electrode catalyst for the MCFC reactor. The selected electrode catalyst with lithium showed high performance. SEM-EDX measurements showed that the added lithium covered the nickel surface and formed stable active species which could not contact with potassium in the molten carbonate salt.