This　paper　mainly　focuses　on　the　synergistic　effect　of　Sn　and　N　dopants　to　enhance　the　photocatalytic　performance　of　anatase　TiO2　under　visible　light　or　simulated　solar　light　irradiation.　The　Sn　and　N　co-doped　TiO2　(SNT-x)　photocatalysts　were　successfully　prepared　by　the　facile　sol-gel　method　and　the　post-nitridation　route　in　the　temperature　range　of　400-550　degrees　C.　All　the　as-prepared　samples　were　characterized　in　detail　by　X-ray　diffraction,　UV-vis　diffuse　reflectance　spectroscopy,　transmission　electron　microscopy,　X-ray　photoelectron　and　electron　spin　resonance　spectroscopy　and　photoelectrochemical　measurements.　The　characterization　results　reveal　that　the　co-incorporation　of　Sn　and　N　atoms　remarkably　modifies　the　electronic　structure　of　TiO2,　which　gives　rise　to　a　prominent　separation　of　photogenerated　charge　carriers　and　more　efficient　interfacial　charge-transfer　reactions　in　a　photocatalytic　process.　The　enhanced　photocatalytic　activity　is　attributed　to　the　intensified　active　oxygen　species　including　hydroxyl　radicals　((OH)-O-center　dot)　and　superoxide　anion　radicals　(O-2(center　dot-))　for　degradation　of　organic　pollutants.　And　the　result　of　photocatalytic　hydrogen　production　further　confirms　the　existence　of　the　synergistic　effect　in　the　SNT-x　samples,　because　they　exhibit　higher　photocatalytic　activity　than　the　sum　of　N/TiO2　and　Sn/TiO2.　This　work　provides　a　paradigm　to　consolidate　the　understanding　of　the　synergistic　effect　of　metal　and　non-metal　co-doped　TiO2　in　domains　of　photocatalysis　and　photoelectrochemistry.