Objective To explore the effect of acupuncture on the chronic progression of migraine without aura and its possible mechanism. Methods The patients with migraine without aura who met the diagnostic criteria were enrolled

including 10 cases in the short course group（disease course≤5 years）

10 cases in the long course group（disease course > 5 years）

and 10 healthy people were set up as the control group. The long course group and the short course group of patients were given acupuncture at affected side Sizhukong（TE23）

Shuaigu（GB8）

Taiyang（EX-HN5）

Fengchi（GB20） and bilateral Hegu（LI4）

Taichong（LR3）

Zulinqi（GB41）

Yanglingquan（GB34）

and Waiguan（TE5）. All acupoints were treated with the even reinforcing-reducing method

keeping the needle for 30 minutes after qi arrival

acupuncture 3 times a week for 4 weeks. The control group was left untreated. The transfer efficiency value of the brain structure network（including the small-world attribute value and the global network efficiency value） of each group of subjects was collected and compared by a magnetic resonance scanner. The visual analog scale was used to evaluate the headache intensity of the 2 groups before and after treatment

and the correlation between the course of the disease and the value of the small world attribute was analyzed. Results Before treatment

there was no significant difference in the small-world attribute values and global network efficiency values of the subjects in all groups（P>0.05）. After treatment

there were significant changes in the short-course group and the long-term group（P<0.05）

and the 2 groups of patients presented different trends（increased in the short course group

decreased in the long course group）; after treatment

the headache intensity of the short course group and the long course group decreased significantly（P<0.05 or P<0.01）. Correlation analysis showed that after acupuncture treatment the value of the small-world attribute of the brain network was negatively correlated with the patient′s course of disease（r=-0.510

P<0.05）. Conclusion Changes in the efficiency of brain structure network information transmission in patients with migraine without aura may be the underlying mechanism of its pathogenesis. Acupuncture may have a two-way adjustment effect

that is

improve the network efficiency of patients with short-term disease and reduce the network efficiency of patients with long-term disease to control intensity of the attack of migraine

thereby alleviating the symptoms.