Disclosed herein is a photoresist composition which includes a norbomene copolymer having an epoxy group, an acid generator, and an organic solvent. The norbomene polymer shows superior mechanical and thermal properties, high transparency, excellent insulating properties, and particularly, improved mechanical properties due to the presence of an epoxy group. The photosensitive resin composition shows superior performance, e.g., transparence, developing properties, residual film characteristics, chemical resistance, heat resistance, and flatness. Particularly, since the photosensitive resin composition enables easy formation of a pattern as an interlayer insulating film and shows a high light transmittance even when being formed into a thin film with a relatively large thickness, it is suitable for the production of an interlayer insulating film used in the fabrication processes of LCDs.