Objective To investigate the improvement effect of 30% supramolecular salicylic acid combined with intense pulsed light on facial post-acne erythema and pigmentation. Methods A total of 186 patients with facial post-acne erythema and pigmentation admitted to Yantai Sogood Medical Cosmetology Hospital from May 2022 to May 2025 were selected. According to the random number table method, they were divided into the control group and the observation group, with 93 patients in each group. The control group was treated with 30% supramolecular salicylic acid, and the observation group was treated with 30% supramolecular salicylic acid combined with intense pulsed light. The clinical efffcacy, improvement time of erythema and pigmentation, scar severity, pigmentation and erythema status were compared between the two groups. Results The total effective rate of the observation group (96.77%) was higher than that of the control group (86.02%) (P<0.05). The improvement time of erythema and pigmentation in the observation group was better than that in the control group (P<0.05). The ECCA score of the observation group after treatment was better than that of the control group (P<0.05). The scores of pigmentation and erythema in the observation group were better than those in the control group (P<0.05). Conclusion 30% supramolecular salicylic acid combined with intense pulsed light can effectively improve the clinical efffcacy of patients with facial post-acne erythema and pigmentation, reduce scar severity, ameliorate pigmentation and erythema, and effectively promote prognosis.