Pt/MgO catalysts were prepared by wet impregnation. At 800°C and atmospheric pressure, Pt/MgO catalysts exhibited a high stability at high gas hourly space velocity of 36,000ml/gh with a CH 4 /CO 2 ratio of 1.0. During 72h time on stream, the conversion of CH 4 and CO 2 remained almost constant, at about 88% and 90%, respectively. There was no loss of Pt. After reaction, the XRD peaks of MgO became broader, indicating amorphization of MgO, which was supported by TEM results. XPS indicated that the reforming reaction had little influence on Pt. CO 2 -TPSR results showed that some carbon deposition occurred under stoichiometric feed of CH 4 and CO 2 , but it did not result in the deactivation of the catalyst. The deposited carbon came mainly from the decomposition of methane.