We successfully fabricated OLED(Organic Light Emitting Diodes) with Al cathodes electrode deposited by the DC magnetron sputtering. The effects of a controlled Al cathode layer of an Indium Tin Oxide (ITO)/blended single polymer layer (PVK Bu:PBD:dye)/Al light emitting diodes are described. The PVK (Poly(N-vinylcarbazole)) and Bu-PBD (2-(4-biphenyl-phenyl)-1,3,4-oxadiazole) are used hole transport polymer and electron transport molecule respectively. We found that both current injection and electroluminescence output are significantly different with a variable DC sputtering power. The difference is believed to be due to the influence near the blended polymer layer/cathode interface that results from the DC power and H$sub$2//O in a chamber. And DC sputtering deposition is an effective way to fabricate Al electrodes with pronounced orientational characteristics without damage occurring to metal-organic interface during the sputtering deposition.