Photodegradation and UV lithographic characteristics of poly (tert-Butyl vinyl ketone) and its copolymers of methyl methacrylate and styrene were investigated in solution and film state. Photodegradation of these polymers takes place th ough Norrish type I reaction. The degradations of poly (tert-Butyl vinyl ketone) and its copolymer were decreased in the presence of oxygen. It was found that photodegradations of these polymers were increased with increase of irradiation temperature. The irradiated films were effectively developed by several developer.