Objective To observe the efffcacy and safety of narrow-band intense pulsed light combined with 15% azelaic acid gel in the treatment of post-acne erythema. Methods A total of 90 patients with post-acne erythema admitted to Jinan Dermatosis Prevention and Control Hospital from September 2023 to June 2025 were selected, and they were divided into the DPL group, the azelaic acid group and the combination group by the random number table method, with 30 patients in each group. The DPL group was treated with DPL alone, the azelaic acid group was treated with topical 15% azelaic acid gel, and the combination group was treated with the aforementioned two therapies in combination. The treatment effect, clinical erythema status, quality of life, adverse reactions and recurrence rate were compared among the three groups. Results The total effective rate of the combination group (86.67%) was higher than that of the DPL group (76.67%) and the azelaic acid group (43.33%) (P<0.05). The scores of CEA and DLQI in the three groups after treatment were lower than those before treatment, and those in the combination group were lower than those in the DPL group and azelaic acid group (P<0.05). There were no statistically signiffcant differences in the incidence of adverse reactions and recurrence rate among the three groups (P>0.05). Conclusion Narrow-band intense pulsed light combined with 15% azelaic acid gel has a definite efficacy in the treatment of post-acne erythema. It can effectively improve erythema symptoms and patients' quality of life, with good safety and tolerance, which is worthy of clinical application.