An　anatase　TiO2　film　sensor　was　prepared　by　a　facile　in-situ　method　on　the　interdigitated　Au　electrode　deposited　on　the　alumina　substrate.　The　structure,　morphology　and　the　optical　properties　of　the　in-situ　TiO2　film　sensor　were　characterized　by　X-ray　diffraction,　Scanning　Electron　Microscopy,　and　UV-vis　diffuse　reflectance　spectra.　The　photo-assisted　gas　sensitivities　of　the　prepared　film　towards　H-2　gas　were　evaluated　at　room　temperature　in　N-2　and　synthetic　air　atmospheres.　As　compared　to　TiO2　film　sensor　prepared　by　drop-coating　method,　this　in-situ　TiO2　film　sensor　exhibited　a　more　compact　structure　composed　of　uniform　TiO2　microspheres　as　well　as　a　better　gas　sensitivity　towards　H-2　under　UV　irradiation,　especially　in　synthetic　air.　The　photo-electrochemical　measurements　suggest　that　these　improvements　may　be　associated　with　the　efficient　charge　transfer　in　the　TiO2　interface　induced　by　the　TiO2　microsphere　structure.　This　study　might　offer　a　feasible　approach　to　develop　photo-assisted　gas　sensors　at　ambient　temperature.