Dry reforming reaction of CH4 by CO2 was carried out over alumina-supported Ni catalysts. Main products were H-2 and CO with small amount of H2O by-production because of reverse water gas shift reaction. The activity was gradually decreased with time on stream by carbon deposition. The addition of Ce component was investigated to improve the catalyst stability. The Ce addition brought decrease of carbon deposition during the reaction. The role of Ce has been considered that an inactive coke formation is significantly suppressed.