||Polymer substrates is one of the key issues of in the flexible displays as such asbased on e-paper, OLED and LCD. Optical transparency, gas barrier layer and chemical resistance were have been studied researched as essential properties. But, for commercialization and substitution of the glass based substrates, performance of polymer substrates have has to be maintained for long time. In this study, we manufactured flexible substrates and suggested methods to evaluate their performance as components for flexible electronics. After repeated bending and high temperature test, changes in optical and barrier propertiesy were measured by optical spectroscopy and MOCON method. Poly ethersulfone(PES) as base film was extruded and coated by wet-process and magnetron sputtering. PES substrates having multi-layer coating showed high light transmittance of 90% and water vapor transmittance rate of below 10-3 g/m2/day, maintained their initial properties after reliability tests.