The　restructuring　of　a　catalyst　under　working　conditions　has　been　recognized　as　a　critical　factor　that　can　significantly　impact　their　performance　in　recent　years.　In　this　study,　we　investigate　the　behavior　of　a　highly　dispersed　Ni　supported　on　TiO2　(P25)　catalyst　during　the　partial　oxidation　of　methane　(POM)　to　produce　syngas.　Our　results　reveal　a　distinct　oscillation　phenomenon　in　the　catalyst＇s　performance　over　time.　The　simultaneous　oscillations　of　rapid　deactivation　and　activation　are　observed,　while　the　catalyst　remains　active　for　continuous　POM　reaction.　Comprehensive　characterizations　suggest　that　this　deactivation　is　not　caused　by　traditional　deactivation　mechanisms　with　coke　formation　or　Ni　sintering.　The　formation　of　inactive　NiTiO3　results　in　catalyst　deactivation,　which　is　formed　between　Ni　and　TiO2　support　in　the　reductive　atmosphere　of　POM　products　under　high　temperature　due　to　strong　metal-support　interaction　(SMSI).　The　simultaneous　presence　of　oxidative　and　reductive　atmospheres　of　the　reactants　and　products　in　the　POM　reaction　leads　to　the　generation　or　demise　of　NiTiO3.　The　dynamic　change　of　the　Ni　active　sites　during　the　in-situ　reaction　leads　to　the　oscillation　of　the　catalytic　activity.　This　study　sheds　new　light　on　the　importance　of　SMSI　in　understanding　the　behavior　of　catalysts　under　working　conditions.