Objective: To observe clinical efficacy of the red, blue lights therapy combined with Erding granule on mild to moderate acne vulgaris. Methods: A total of 120 patients with mild to moderate acne vulgaris were randomly divided into a control group (n=62) and an experiment group (n=58). The patients in the 2 groups accepted the therapy of red and blue lights (twice a week) combing with external application of fusidic acid cream (once every morning and night). Erding granule was added to the experiment group orally, 4 g each time, 3 times a day. The duration for treatment was 4 weeks for both groups. The skin lesions and the drug adverse reaction were observed. The curative effects in both groups were compared. Results: The effective rates at the 4th week was 87.10% in the experiment group was 87.10% and 53.45% in the control group, respectively, with a significant difference between these two groups (P<0.01). Conclusion: Treatment of acne vulgaris with the combination of red, blue lights and erding granule can achieve good curative effects and safety.