The effect of Mg/Al molar ratio for steam reforming reaction of methane was studied with four Ni-based catalysts prepared by reduction of hydrotalcite-like precursors. To characterize these catalysts, XRD, BET and TPR experiments were performed, and the results were compared with those of commercial catalyst, HRC. All the Ni-supported hydrotalcite-like catalysts showed higher activity than HRC. The main reason for higher activity was the different Ni crystallite size and surface area. As the Mg/Al molar ratio decreased from 9 to 1, the structure of hydrotalcite was developed well resulting in the smaller crystallite size of Ni due to more homogeneous mixed oxide produced.