Photodegradation and photographic characterisitics of polymethyl isopropenyl ketone (PMIK) and polyphenyl vinyl ketone (PPhVK) films were investigated. The UV spectra of PMIK and PPhVK in dioxane showed absorption bands in regions, 250-335 nm (λmax=290, εmax=45), and 300-380 nm (λmax=323, εmax=89), respectively. The irradiated PPhVK films is developed by ethyl cellosolve well though the PMIK by methyl cellosolve. It was found that sensitivity of PMIK was inceeased with the increase of molecular weight Mn , and the elevetion of temperature during irradiation. However, the relative sensitivity (S) of the PPhVK and Mn bear a linear relationship to each other; i.e. S=365-1.93×10-3 Mn .