Objective To investigate the effect of subcision combined with low-energy fractional CO? laser in the treatment of facial depressed acne scar. Methods A total of 82 patients with facial depressed acne scar admitted to Dangui Street Medical Aesthetic Clinic of Hangzhou Shuangmei Health Management Co., Ltd. from January to October 2024 were selected and divided into the control group and the study group by random number table method, with 41 patients in each group. The control group was treated with low-energy fractional CO? laser, and the study group was treated with subcision combined with low-energy fractional CO? laser. The clinical symptom improvement, serum inflammatory indicators and clinical efficacy were compared between the two groups. Results The edema duration, erythema duration, incrustation time, decrustation time and healing time in the study group were all shorter than those in the control group (P <0.05). The ECCA score of the two groups after treatment was lower than that before treatment, and that of the study group was lower than that of the control group (P <0.05). The levels of TNF-α, IL-10, and IL-7 in the two groups after treatment were lower than those before treatment, but there were no significant difference between the two groups after treatment (P >0.05). The total effective rate of treatment in the study group (95.12%) was higher than that in the control group (80.49%) (P <0.05). Conclusion The application effect of low-energy fractional CO? laser combined with subcision in the treatment of facial depressed acne scar is definite, which can promote the improvement of clinical symptoms and does not increase the body's inflammatory response.