Basal cell carcinoma and squamous cell carcinoma are the two most common skin cancers in clinical practice. In the past, the main treatment methods were surgery, freezing, laser, drugs, etc., which often have unsatisfactory effects and are prone to adverse consequences such as pain, dermatitis, disfigurement, and deterioration of the disease, adding more pain to patients. In fact, for early-stage basal cell carcinoma and squamous cell carcinoma (superficial type or solid type within 1.5cm in diameter), photodynamic therapy should be the preferred treatment method. The principle is that malignant tumor cells can selectively absorb exogenous photosensitizer and convert into protoporphyrin intracellularly, and then undergo photodynamic reaction after irradiation by specific wavelength of red light, which generates reactive oxygen species and kills tumor cells, while surrounding normal tissue cells are not affected in any way. At present, clinical treatment is mostly done in a dark room environment, with 10% amino ketopentanoic acid solution applied wet on the surface of the skin lesion or tumor, covering an area of about 1cm beyond the edge of the skin lesion, the film is sealed for 3 hours and the porphyrins are detected by 395nm UV lamp, and the brick-red fluorescence can continue to be irradiated by the photodynamic therapy instrument, the light spot is adjusted according to the size of the skin lesion, and each irradiation lasts about 30 minutes. The total dose of each irradiation is controlled at 72~100J/cm2, and the next treatment will be conducted after 1~2 weeks. Usually, after 2-6 treatments, the overall cure rate can reach 95-100%, and only a very small number of people experience local stinging pain and other adverse effects, but they can be tolerated. As a new type of ablative therapy for body surface tumors, photodynamic therapy demonstrates great advantages in the early treatment of basal cell carcinoma and squamous cell carcinoma with less pain, easy operation and good efficacy.