The effect of ceria promotion over Ni/Al2O3 catalysts on the catalytic activity and coke formation was investigated in combined steam and carbon dioxide reforming of methane (CSCRM) to produce synthesis gas (H-2/CO = 2) for gas to liquid (GTL) process. Ce-promoted Ni/Al2O3 catalysts were prepared by co-impregnation method. It has been found that the Ce promotion over Ni/Al2O3 catalyst is beneficial to catalytic activity and coke resistance. As a result, the catalyst promoted with 6 wt% Ce exhibits the highest activity as well as high coke resistance due to the improvement of Ni dispersion and high oxygen storage capacity of CeO2.