Objective To explore the effect of carbon dioxide fractional laser therapy in patients with chronic wounds. Methods A total of 90 patients with chronic wounds admitted to the Department of Dermatology and Venereology of Taixing Hospital of Traditional Chinese Medicine from September 2021 to February 2024 were selected as the research objects. According to different treatment methods, they were divided into reference group and experimental group, with 45 patients in each group. The reference group was treated with recombinant human basic fibroblast growth factor for external use, and the experimental group was treated with carbon dioxide fractional laser on the basis of the reference group. The clinical efficacy, pain degree, wound granulation and adverse reactions were compared between the two groups. Results The total effective rate of the experimental group was 95.56%, which was higher than 80.00% of the reference group (P <0.05). The pain degree in the experimental group was lower than that in the reference group (P <0.05). The scores of color and texture of wound granulation in the experimental group were higher than those in the reference group after 7, 14 and 28d of treatment (P <0.05). The incidence of adverse reactions in the experimental group was 4.44%, which was lower than 6.67% in the reference group, but the difference was not statistically significant (P >0.05). Conclusion The application of carbon dioxide fractional laser in patients with chronic wounds has a definite effect, which can promote the growth of wound granulation and will not increase the incidence of adverse reactions. It is worthy of clinical application.