Objective To analyze the efffcacy and safety of supramolecular salicylic acid peeling combined with red and blue light in the treatment of patients with moderate to severe cystic acne. Methods A total of 80 patients with moderate to severe cystic acne admitted to Rui’an PAN Haiyan Dermatology Clinic from January 2024 to January 2025 were selected, and they were divided into the control group and the observation group by the random number table method, with 40 patients in each group. The control group was treated with supramolecular salicylic acid peeling, and the observation group was treated with supramolecular salicylic acid peeling combined with red and blue light. The clinical efffcacy, skin barrier function, acne scar severity and adverse reaction rate were compared between the two groups. Results The total effective rate of the observation group (97.50%) was higher than that of the control group (80.00%) (P<0.05). The sebum content and transepidermal water loss of the observation group at 8 weeks after treatment were lower than those of the control group, and the stratum corneum hydration was higher than that of the control group (P<0.05). The scores of IGA and ECCA in the observation group at 8 weeks after treatment were lower than those in the control group (P<0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P>0.05). Conclusion The combined treatment of supramolecular salicylic acid peeling and red and blue light is more effective than single supramolecular salicylic acid peeling in the treatment of moderate to severe cystic acne. It can effectively promote the regression of skin lesions, improve skin barrier function, and does not increase the incidence of adverse reactions, with good efffcacy and safety.