Due　to　the　high　stability　and　chemical　inertia　of　methane,　CH4,　its　selective　conversion　into　value-added　organic　chemicals　under　mild　conditions　has　been　widely　regarded　as　an　important　reaction　for　the　chemical　industry.　Here,　we　develop　a　RuOx　decorated　ZnO/CeO2　photocatalyst　for　the　highly　efficient　and　selective　transformation　of　CH4　into　CH3OH　under　simulated　solar　light　irradiation.　The　CH3OH　generation　rate　over　the　optimized　RuOx/ZnO/CeO2　composite　is　133.54　mu　mol　g(-1)　h(-1)　with　97.7%　selectivity,　which　is　20　times　higher　than　that　of　a　ZnO/CeO2　reference　system　(6.56　mu　mol　g(-1)　h(-1))　which　only　exhibits　moderate　selectivity　(40.5%).　We　find　that　the　significant　boost　to　the　photocatalytic　performance　is　attributable　to　accelerated　interfacial　charge　separation　and　a　beneficial　rise　in　free　hydroxyl　radical　generation　from　water　oxidation　in　the　presence　of　RuOx　clusters.