The catalytic behavior of Ni/Ce-ZrO2/θ-Al2O3 has been investigated in the partial oxidation of methane (POM) toward synthesis gas. The catalyst showed high activity and selectivity due to the heat treatment of the support and the promotional effect of Ce-ZrO2. It is suggested that the support was stabilized through the heat treatment of γ-Al2O3 and the precoating of Ce-ZrO2, on which a protective layer was formed. Moreover, sintering of the catalyst was greatly suppressed for 24 h test. Pulse experiments of CH4, O2 and/or CH4/O2 with a molar ratio of 2 were systematically performed over fresh, partially reduced and well reduced catalyst. Results indicate that CH4 can be partially oxidized to CO and H2 by the reactive oxygen in complex NiOx species existing over the fresh catalyst. It is demonstrated that POM over Ni/Ce-ZrO2/θ-Al2O3 follows the pyrolysis mechanism, and both the carbonaceous materials from CH4 decomposition over metallic nickel and the reactive oxygen species present on NiOx and Ce-ZrO2 are intermediates for POM.