Objective: Research on the photodynamic therapy of malignancy of skin with He-Ne Laser. Methods: 35 cases of skin malignancy were treated with photodynamic therapy. He-Ne laser with output power of 600 mW was used and hematoporphyrin derivative (HPD) was applied, at a dose of 5mg/kg of body. 15 patients received simple surface irradiation, 20 patients received both surface and insertion irradiation. 28 patients underwent treatment for one time, 7 patients twice. The 12 cases were basel cell carcinoma, 7 cases were squamous cell carcinoma, 4 cases were skin carcinoma in situ, 8 cases were skin Paget's disease, 1 case was Paget's disease accompanying adenoid carcinoma, 1 case malignant melanoma, 1 case red hypertrophic disease, 1 case recurrent perianal carcinoma deriving from rectum.