Objective To explore the effect of topical application of recombinant type Ⅲ humanized collagen combined with CO2 fractional laser therapy on wound healing time in patients with skin scar. Methods A total of 80 patients with skin scar who visited the Dermatology Hospital of Guangxi Zhuang Autonomous Region from January 2022 to January 2024 were selected as the research subjects, and they were divided into the control group and the observation group by the random number table method, with 40 patients in each group. The control group was treated with CO? fractional laser alone, and the observation group was treated with topical application of recombinant type Ⅲ humanized collagen combined with CO? fractional laser. The wound healing time, clinical efficacy, patient satisfaction and adverse reactions were compared between the two groups. Results The wound healing time of the observation group was shorter than that of the control group (P <0.05). The total effective rate of the observation group (97.50%) was higher than that of the control group (95.00%), but the difference was not statistically significant (P>0.05). The marked effective rate of the observation group (95.00%) was higher than that of the control group (77.50%) (P <0.05). The patient satisfaction of the observation group (92.50%) was higher than that of the control group (72.50%) (P <0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P >0.05). Conclusion Topical application of medical recombinant type Ⅲ humanized collagen combined with CO? fractional laser in the treatment of skin scar can effectively shorten wound healing time, improve scar improvement effect and patient satisfaction, without increasing adverse reactions.