The energy transfer process of phosphorescent dye PtOEP (2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum(II) doped organic molecule Alq (tris(8- hydroxyquinoline) aluminum) thin films were studied by steady-state spectrum and time-resolved spectrum. The energy transfer efficiency and critical radius of the doped thin films were estimated from the overlap integral between the absorption spectra of PtOEP and the fluorescent spectra of Alq based on Frster theory. The experimental results from steady fluorescent spectra were approximately consistent with the estimation, which indicates that Frster energy transfer mechanism is operative in dye doped organic thin films. The experimental results from time-resolved fluorescent spectroscopy show that the fluorescent lifetime of Alq in the doped thin films decreases gradually with the doping concentration, indicating that there is an efficient energy transfer from Alq to PtOEP in the doped thin films.