Objective To analyze the clinical value of carbon dioxide fractional laser cosmetology in the treatment of scar after acne. Methods A total of 100 acne patients with scars admitted to our hospital from September 2019 to September 2022 were randomly divided into control group and study group, with 50 patients in each group. The control group was treated with conventional drugs, and the study group was treated with carbon dioxide fractional laser cosmetology. The clinical efficacy, aesthetic satisfaction and skin lesion count were compared between the two groups. Results The total effective rate of treatment in the study group was 98.00%, which was higher than 84.00% in the control group (P <0.05). The aesthetic satisfaction of the study group was higher than that of the control group (P <0.05). After treatment, the number of skin lesions in the study group was less than that in the control group (P <0.05). Conclusion Carbon dioxide fractional laser cosmetology has a positive effect on the treatment effect, skin lesion status and appearance aesthetics of acne patients with scars.