Scar of skin is hard to be treated clinically. The transplantation of stem cells has provided a new method for the treatment of the disease in recent years. In order to evaluate the therapeutic effect of stem cells on skin scar and find the effective methods of treatment for the disease, we reviewed recent studies on the effectiveness of using stem cells to treat skin scar. Many studies have been reported that several types of stem cells were used to treat skin scar clinically and all the curative effects were satisfactory. However, many obstacles remain to be overcome in stem cells-skin scar clinically. These obstacles include as following: the type-selectively effectiveness of stem cells to skin scar; the criterions of administration route, concentration, dose and safety; the insight and mechanism into the action. It is believed that the viable solutions of the above obstacles will have a significant impact on the way to the clinical application of stem cells-skin scar treatment.