The present invention provides polyimide applied to the buffer coating of semiconductors and a photosensitive resin composition including the same. The polyimide is a polyimide polymer represented by Chemical Formula 1 below. Further, the present invention provides a photosensitive resin composition, including 1) BDA-series soluble polyimide having an i-ray permeability of 70% or more; 2) a polyamic acid having elongation of 40% or more; 3) a novolak resin, and 4) diazonaphthoquinone-series photosensitive substance and having a high resolution, high sensitivity, an excellent film characteristic, and mechanical physical properties which are the requirements of semiconductor buffer coating.