Objective To analyze the effect of carbon dioxide fractional laser for cosmetic treatment of skin diseases. Methods A total of 66 patients with skin diseases admitted to our hospital from January 2023 to December 2023 were selected and divided into control group and experimental group by random number table method, with 33 patients in each group. The reference group was treated with topical drugs, and the experimental group was treated with carbon dioxide fractional laser cosmetic therapy. The clinical efficacy, wound granulation status and skin lesion count were compared between the two groups. Results The total effective rate of treatment in the experimental group was 96.97%, which was higher than 81.82% in the reference group (P <0.05). The scores of granulation texture and color after treatment in the experimental group were higher than those in the reference group (P <0.05). The skin lesion counts of nodules, pustules, cysts and papules after treatment in the experimental group were less than those in the reference group (P <0.05). Conclusion Carbon dioxide fractional laser for cosmetic treatment of skin diseases has a good clinical effect, which can effectively reduce skin lesions, improve wound granulation status, and help to improve the overall aesthetics.