As a non-drug treatment, photodynamic therapy (PDT) has shown good effects and low side effects in the treatment of a variety of diseases, and has broad application prospects. In recent years, PDT has become increasingly important in the diagnosis and treatment of digestive system diseases, especially in the treatment of gastrointestinal tumors and gastrointestinal inflammation. This article reviews the research progress and clinical applications of PDT in the treatment of various digestive diseases. Through literature review, the advantages of PDT in the treatment of different types of digestive diseases are summarized, and the limitations of its clinical applications are discussed. The development direction of PDT in medical diagnosis and treatment is projected, and the technological innovation of photosensitizer and the possibility of its use as a routine treatment for other diseases are proposed. Despite some limitations, the development prospects of PDT in clinical application are still broad, and it is expected to provide new directions and ideas for the treatment of diseases.