Objective To explore the cosmetic effect of ultra-pulsed fractional CO2 laser+micro-needle knife subcutaneous release in the treatment of acne atrophic scar and its influence on patient satisfaction. Methods A total of 100 patients with acne atrophic scar admitted to the Affiliated Hospital of Yanbian University from November 2023 to November 2024 were selected, and they were divided into group A and group B by the random number table method, with 50 patients in each group. Group A was treated with excision and suture, and group B was treated with ultra-pulsed fractional CO2 laser+micro-needle knife subcutaneous release. The scar condition, cosmetic satisfaction, treatment effect and adverse reaction rate were compared between the two groups. Results After treatment, the scores of scar hyperemia, scar thickness, scar flexibility and total score in group B were lower than those in group A (P <0.05). The satisfaction rate in group B (96.00%) was higher than that in group A (80.00%), the total effective rate of treatment (98.00%) was higher than that in group A (76.00%), and the incidence of adverse reactions (6.00%) was lower than that in group A (18.00%) (P <0.05). Conclusion Ultra-pulsed fractional CO2 laser+micro-needle knife subcutaneous release has a good effect in the treatment of patients with acne atrophic scar. It can accelerate scar repair, improve patients' cosmetic satisfaction, and reduce the risk of adverse reactions.