A potassium and calcium co-promoted nickel catalyst (KCaNi/alpha-Al2O3) prepared by a direct impregnation method possessed a high activity, high stability and excellent coke resistance properties in CH4 reforming with CO2. XRD, XPS and H-2-TPR characterizations indicated that (i) Ca and K strengthened the interaction between Ni and alpha-Al2O3 and promoted the formation of a unique NiAl2O4 phase on the surface of the catalyst and (ii) Ca and K increased the dispersion of Ni and retarded its sintering. Coking reactions (CH4 temperature-programmed decomposition and O-2-TPO) disclosed that K reduced carbon formation via CH4 decomposition.