A　novel　application　of　a　nano-sized　titanium　dioxide　(TiO2)　photocatalyst　for　improving　the　performance　of　the　ceramic　insulator　under　contaminated　conditions　is　proposed　in　this　paper.　The　TiO2-coated　insulator　was　prepared　by　spraying　a　certain　amount　of　TiO2　sol　on　the　ceramic　insulator　followed　by　subsequent　calcination.　The　physical　and　chemical　properties　of　the　TiO2　film　were　studied　and　their　influences　on　the　self-cleaning　and　electrical　performances　of　the　ceramic　insulator　were　evaluated.　Compared　with　the　uncoated　insulators,　the　as-prepared　TiO2-coated　insulator　exhibited　an　enhanced　self-cleaning　ability　in　a　heavy　polluted　environment　because　of　the　excellent　photo-induced　catalytic　performance　of　the　TiO2　film.　Moreover,　the　TiO2-coated　insulators　presents　a　flashover　voltage　level　similar　to　normal　ceramic　insulators,　and　even　a　higher　performance　of　wet　flashover　than　the　latter.　It　was　proposed　that　the　semiconducting　property　and　the　hydrophilicity　of　TiO　2　films　could　be　responsible　for　the　promoting　effect　on　the　electrical　performances　of　the　porcelain　insulator.　This　study　shows　that　coating　TiO2　films　on　the　surface　of　insulators　may　have　a　promise　in　preventing　pollution　flashover.　©　2009　The　American　Ceramic　Society.