Objective:To observe the clinical effect of syndrome differentiation acupuncture therapy on chronic migraine. Methods200 patients of chronic migraine were randomized into treatment group and control group,100 cases in each group. The treatment group was treated with syndrome differentiation acupuncture therapy,while control group was treated with conventional western medicine. The treatment course was 46 days in each group,with a follow-up of 2 weeks. Clinical efficacy was observed. Changes of chronic migraine score,incubation and amplitude of SSR were compared.  Results:①180 cases completed the trail,among which 94 cases in treatment group and 86 cases in control group. ②The total effective rate of treatment group and control group were 92.55% and 84.88%. The difference of clinical efficacy was statistically significant(P<0.05). ③Compared before and after the treatment,the total chronic migraine score in each group was obviously decreased(P<0.05), while the total chronic migraine score in treatment group decreased obviously than that of control group after the treatment(P<0.05). ④Compared before and after the treatment,incubation of SSR in the two groups were shot than before(P<0.05), and amplitude of SSR in treatment group increased obviously(P<0.05). After the treatment,the difference of incubation and amplitude of SSR was statistically significant(P<0.05).  Conclusion:The effect of syndrome differentiation acupuncture therapy on chronic migraine was satisfying. It can relieve the headache significantly with a possible mechanism of improving autonomic nervous system function.