Photodynamic therapy (PDT) is known as a prospective cancer treatment. However, patients experience the inconvenience from living in the dark room for several weeks as photosensitizer is also activated by sunlight patients. In this research, we developed tumor environment sensitive polymeric photosensitizers. Tumor environments include low pH and high expression of enzyme. Tumor environment responsive polymeric photosensitizers show selective photoactivity only in the tumor by recognizing low pH or high enzyme concentration, thus it induces fewer side effects than conventional photosensitizers and enable tumor specific photodynamic therapy. It is expected that it will enhance not only the photodynamic therapy efficacy but also the convenience of patients who are receiving photodynamic therapy.