SignificanceHematoporphyrin Monomethyl Ether (HMME) is a promising photosensitizer for photodynamic therapy (PDT) and has been widely applied in the treatment of port-wine stains (PWS). ApproachPatients with PWS were treated with HMME-PDT, and efficacy was evaluated by comparing photographs and CDFI examination. Results9 of the 33 cases were cured (27.27%), 10 indicated a good efficacy (30.30%), 11 showed alleviation (33.33%), while 3 had no obvious efficacy (9.09%). The efficacy was related to the types of lesions and the total number of therapeutic sessions. More sessions the purple type and nodular thickening type received, better clinical cosmetic results were. CDFI may be an excellent technique to evaluate efficacy. ConclusionsHMME-PDT serves as a safe and effective approach for improving PWS. The clinical therapeutic effect is affected by the type of lesions and the total number of therapeutic sessions. CDFI examination may be an excellent evaluation method.