Objective To analyze the application effect of carbon dioxide laser in skin cosmetology. Methods A total of 70 patients admitted to the Department of Dermatology and Cosmetology of our hospital from June 2021 to June 2022 were selected as the research objects. They were divided into observation group and control group by random number table method, with 35 patients in each group. The control group was given conventional treatment, and the observation group was given carbon dioxide laser treatment. The clinical efficacy, skin lesions, skin conditions and pain degree of the two groups were compared. Results The total effective rate of treatment in the observation group was 100.00%, which was higher than 88.57% in the control group, the difference was statistically significant (P<0.05). After treatment, the number of pigmented nevus, verrucous nevus, sebaceous nevus and papilloma in the observation group was less than that in the control group, the difference was statistically significant (P<0.05). After treatment, the scores of skin color and texture in the observation group were higher than those in the control group, and the VAS score was lower than that in the control group, the difference was statistically significant (P<0.05). Conclusion The application of carbon dioxide laser in skin cosmetology is effective, which can effectively improve the skin color and texture of patients, promote the recovery of skin lesions, and reduce pain, with higher certain clinical application value.