Objective To evaluate the efficacy of combined red and blue light therapy with acne film coating in treatment of moderate and severe acne.Methods Totally 547 patients with moderate or severe acne were enrolled in the study from March 2012 to July 2014.Using open control,according to the cycle of time sequence will patients were divided into three groups:183 patients (study group) were received alternatively red and blue light therapy twice a week,and acre film coating was applied once a day;182 patients in control group 1 received film coating alone and another 182 patients (control group 2) received light therapy alone.The treatment lasted for 6 weeks in all three groups.The numbers of skin lesions were recorded before and 2,4,6 w after treatment,and the curative effect was evaluated 10 w after treatment.Results The number of skin lesion were significantly reduced 6w after treatment in all three groups,that for study group was most markedly.For patients with moderate acne,the total effective rates in study group and in control groups 1 and 2 were 84.6％ (110/130),58.5％ (76/130) and 51.9％ (67/129),respectively (x2 =21.836,and 31.955,P ＜0.01).For patients with severe acne the total effective rates in study group and in control groups 1 and 2 were 84.9％ (45/53),57.7％ (30/52) and 56.6％ (30/53),respectively (x2 =9.525 and 10.258,P ＜0.01).There are 20 cases in observation group therapy for different degree of erythema,itching,burning,tingling,incidence of side effects was 10.9％ (20/183),control group 1 and 2 were 7.1％ (14/182),12.1％ (22/182),are tolerated.Conclusion The combination of red/blue light therapy with acne film coating is more effective than the application of single method alone for patients with moderate or severe acne.