Disclosed herein is a photoresist composition suitable for coating onto a large substrate and having improved coating uniformity to prevent occurrence of stains, a coating method thereof, a method of forming an organic film pattern using the same, and a display device fabricated thereby. The present invention thus provides a photoresist composition comprising a polymeric resin with an incorporated polysiloxane resin, a photosensitive compound, and an organic solvent. Accordingly, the photoresist composition can be coated onto a large substrate by a spinless coating method, and thereby coating uniformity can be improved, the occurrence of stains such as cumulous stains and resin streaks can be prevented, and the coating rate and quality of a final product prepared using the photoresist composition can also thereby be enhanced.