The Ni-supported catalysts have been prepared in situ by the solid phase crystallization (spc) method starting from layered double hydroxides (LDHs) as the precursor and tested for the partial oxidation of methane to synthesis gas. The spc-Ni/M-Al (M: Mg, Ca and Sr) catalysts were prepared from Ni-M/Al-LDHs as the precursors, and the activities were studied in relation to the structure of the catalysts and compared with those prepared by the impregnation method. Among the catalysts tested, spc-Ni/Ca-Al was easily reduced to form active Ni metal particles during the reaction and showed the highest activity and selectivity to synthesis gas production as well as the highest sustainability against coke formation on the catalyst. The high activity and the high sustainability against coke formation of spc-Ni/Ca-Al may be due to the stable and highly dispersed Ni metal particles in addition to the basic property of Ca-Al mixed oxide as the support.