An efficient polymer light emitting diode (PLED) was fabricated by inserting calcium (Ca) between a emissive layer and anAluminum (Al) cathode. An efficient cathode Ca/Al used to improve the performance of PLEDs was reported. Indium tin oxide (ITO) /poly (3, 4ethylenedioxythiophene) : polystyrenesulfonate (PEDOT:PSS) / 2, 3-dibutoxy-1, 4-poly (phenylenevinylene) (DBPPV) / Ca/Al devices showed dramatically enhanced electroluminescent (EL) brightness and efficiency. The optimized DBPPV layer concentration device with the 60 nmlayer of Ca with cathode structure of Ca/Al showed the improved current efficiency than the control device of the Cesiumfluoride (CsF) /Aluminumcathode. The drive voltage of the device with the Ca/Al cathode was decreased compared with CsF/Al device. The enhanced properties of the device with such a cathode are considered to the improved balance of electron/hole injection in the emitting layer.