Objective To explore the effect of cosmetic repair technology in the treatment of skin scar. Methods A total of 100 patients with facial soft tissue injury admitted to the Department of Dermatology and Venereology, Changsha Central Hospital Affiliated to University of South China from June 2022 to June 2023 were selected as the research objects. According to the random number table method, they were divided into control group and observation group, with 50 patients in each group. The control group received routine treatment, and the observation group was treated with cosmetic repair technology. The clinical efficacy, quality of life, complication rate, deformity rate and scar hyperplasia rate were compared between the two groups. Results The excellent and good rate of repair in the observation group was 96.00%, which was higher than 80.00% in the control group (P <0.05). After treatment, the scores of mental state, body pain, social function and emotional function in the observation group were higher than those in the control group (P <0.05). The incidence of complications in the observation group was 6.00%, which was lower than 18.00% in the control group (P <0.05). The incidence of deformity and scar hyperplasia in the observation group were lower than those in the control group (P <0.05). Conclusion The application of cosmetic repair technology in the treatment of skin scar is effective. It can not only improve the treatment effect and reduce the incidence of complications, but also effectively prevent deformity and scar hyperplasia, which is helpful to improve the quality of life of patients.