Photodynamic therapy(PDT) is a new technology which uses the photodynamic effect in disease diagnosis and treatment. It is based on photodynamic effect, which is dynamic reaction process, in which oxygen molecules participated with the biological effects happened. At first, PDT was invented to treat various cancers,but with the development of second generation of photosensitizer, PDT has been increasingly used in the treatment of eye diseases, and the efficacy is outstanding. This paper will give an overview on the application of PDT in eye diseases.