We fabricated PEN substrates coated with photo-polymerizable acrylate layer to produce three dimensional network structures of barrier for the application of flexible display. Components for the photo-curable resin composed of multi-functionallized acrylates were synthesized, successfully. It is found that the photo-polymerized organic layer on PEN substrate could enhance surface properties of the pristine substrate. The surface roughness and optical transparency were measured to evaluate and optimize the organic/inorganic treatment on PEN substrate for application of flexible devices.