Objective To investigate the effect of Yiqi Jianpi Chushi decoction combined with red and blue light on skin lesions and pigmentation in patients with moderate to severe acne. Methods A total of 80 patients with moderate to severe acne admitted to Ningxia Hospital of Integrated Traditional Chinese and Western Medicine from January to December 2023 were selected and randomly divided into control group and observation group, with 40 patients in each group. The control group was treated with red and blue light, and the observation group was treated with Yiqi Jianpi Chushi decoction combined with red and blue light. The skin lesions and pigmentation, treatment effect, traditional Chinese medicine syndrome scores and adverse reactions were compared between the two groups. Results The number of skin lesions and acne pigmentation score in the observation group after treatment were better than those in the control group (P<0.05). The total effective rate of treatment in the observation group was 95.00%, which was higher than 72.50% in the control group (P<0.05). After treatment, the scores of flushed complexion, skin greasy and rash pain 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 effect of Yiqi Jianpi Chushi decoction and red and blue light therapy in the treatment of patients with moderate to severe acne is good, which can effectively reduce the skin lesions and acne pigmentation, improve the traditional Chinese medicine symptoms, and will not increase the incidence of adverse reactions. The treatment is safe.