Objective To observe the efficacy and safety of picosecond laser combined with ablative CO? fractional laser and subcision in the treatment of atrophic acne scar. Methods A total of 90 patients with atrophic acne scar admitted to our hospital from January 2023 to April 2024 were selected as the research subjects. According to the random number table method, they were divided into control group 1, control group 2 and experimental group, with 30 patients in each group. Control group 1 was treated with subcision, control group 2 was treated with picosecond laser combined with ablative CO? fractional laser, and the experimental group was treated with picosecond laser combined with ablative CO? fractional laser and subcision. The treatment effect, ECCA score, pain condition and adverse reactions were compared among the three groups. Results After 3 months of treatment, the VSS score of the experimental group was lower than that of control group 1 and control group 2, and the difference was statistically significant (P <0.05). The ECCA score of the experimental group after treatment was lower than that of control group 1 and control group 2, and the difference was statistically significant (P <0.05). There was no significant difference in the VAS score among the three groups (P >0.05). The incidence of adverse reactions in control group 1, control group 2, and the experimental group was 10.00%, 20.00%, and 13.33% respectively, and there was no significant difference in pairwise comparisons among the three groups (P >0.05). Conclusion The application of picosecond laser combined with ablative CO? fractional laser and subcision in treatment of atrophic acne scar is superior to subcision alone and the combination of picosecond laser and ablative CO? fractional laser in terms of therapeutic effect. This method will not increase the incidence of postoperative adverse reactions and pain in patients, and accelerate the recovery of patients, which is worthy of clinical application.