Abstract: A certain amount of nano-sized TiO2 colloid was sprayed on the ceramic insulator surface to prepare the photo-induced self-cleaning insulators with subsequent heat treatment. The crystal form, grain size, morphology and thickness of the nano-TiO2 film coated on the ceramic surface were characterized by X-ray diffraction, transmisson electron microscopy and scanning electron microscopy. The effects of nano-TiO2 film on the self-cleaning and electrical properties of the ceramic insulators were evaluated by the artificial accelerated polluted test and the AC withstand test. The results show that the average nonsoluble deposit density (NSDD) value of the TiO2-coated insulators was only 47% that of the normal ceramic insulators, and the AC withstand voltage level of the former was 9.4% higher than that of the latter.