A method for forming a pixel-defining layer on an OLED panel is disclosed. The method comprising (A) providing a substrate; (B) forming a plurality of first electrodes in parallel stripes; (C) forming a layer of photosensitive polyimide or polyimide precursor compositions with patterns; and (D) baking said substrate with patterned photosensitive polyimide or polyimide precursor compositions for crosslinking or curing. An OLED panel made by above method is also disclosed here.