Thin polyimide films were deposited for hole blocking layer of EL device by the novel physical vapor deposition method, Ionized Cluster Beam Deposition (ICB). EL devices of Glass/ITO/PI/BEH-PPV/Al structure using spin coating and the ICB deposition technique were fabricated. By inserting a PI interlayer with various thickness and packing density, I-V and I-L characteristics, electroluminescence spectra and quantum efficiency of the devices were investigated in order to determine the role of the PI interlayer between ITO and BEH-PPV.