Objective To explore the effect of 30% supramolecular salicylic acid combined with red and blue light in the treatment of acne vulgaris. Methods A total of 90 patients with acne vulgaris admitted to our hospital from August 2021 to December 2022 were selected as the research objects. They were divided into control group and observation group by random number table method, with 45 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 red and blue light. The immune function indexes and serum in?ammatory factors were compared between the two groups. Results After treatment, CD3+, CD4+ and CD4+/CD8+ in the observation group were higher than those in the control group, and CD8+ was lower than that in the control group (P<0.05). After treatment, IL-10 in the observation group was higher than that in the control group, IL-18 and TNF-α were lower than those in the control group (P<0.05). Conclusion 30% supramolecular salicylic acid combined with red and blue light is effective in the treatment of acne vulgaris, which can effectively improve the immune function, and has a positive effect on improving serum in?ammatory mediators.