Photodynamic therapy (PDT) has been widely used in clinical fields and done by three components: photosensitizers (PSs), light and oxygen. Under the action of PS as an energy transforming media, the light energy is converted to chemical energy to make effects on target. In the process of PDT, its effect is determined a lot by the parameter of light and the characteristics of PSs. With the development of light source and photosensitizer, the application of PDT has been investigated in oral diseases. This review mainly focused on the effect of PDT on non-tumor diseases of oral cavity, including endodontic, periodontal and mucosal problem. Compared with the normal therapy, the combination therapy with PDT could obtain better efficacy. It was suggested that PDT showed great advantages as an adjuvant therapy in the above oral diseases. Through a further improvement, PDT is expected to play an increasingly important role on the oral disease treatment in the future.