High-efficiency red polymer phosphorescent light-emitting diodes(PLEDs) have been fabricated based on czrbazole-substituted porphyrin platinum(6CPt)complex and PBD-doped PFO(poss). The best external quantum efficiency of 5.68% has been achieved. The effect of PBD on the device performance was analyzed. We found that PBD improves the energy transfer of excitons from host PFO to guest triplet complex 6CPt.