Objective To compare the cumulative analgesic effects of electroacupuncture at Sanyinjiao (SP6), Xuanzhong (GB39) and non-acupoint in treating primary dysmenorrhea. Method By adopting a multi-centered randomized controlled study method, 501 patients recruited from Dongzhimen Hospital of Beijing University of Chinese Medicine, China-Japan Friendship Hospital, Beijing Hospital of Traditional Chinese Medicine of Capital Medical University, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Huguosi Hospital of Chinese Medicine of Beijing University of Chinese Medicine and the Outpatient of Shandong University of Traditional Chinese Medicine were randomized into a Sanyinjiao group, a Xuanzhong group, and a non-acupoint group, 167 subjects in each group. The electroacupuncture intervention was applied when dysmenorrhea flared up and the Visual Analogue Scale (VAS) ≥40 mm, with frequency at 2/100 Hz and intensity during patient’s endurance, 30 min each time, once a day, and for successive 3 d. Before the first treatment, 30 min after the first treatment, and respectively prior to the second and third treatment, VAS was used to measure the pain intensity. Meanwhile, the Retrospective Symptom Scale (RSS-COX 2) was investigated before the first treatment, right after the removal of needles for the first treatment, before the second and third treatment. Result The decrease of VAS in Sanyinjiao group was more significant than that in Xuanzhong group and non-acupoint group (MD=﹣2.92 mm, P=0.028; MD=﹣3.47 mm, P=0.009), while there was no significant difference between Xuanzhong group and non-acupoint group (MD=﹣0.56 mm, P=0.674); there were no significant differences in comparing the RSS-COX2 total score among the three groups (P=0.086). Conclusion Sanyinjiao (SP6) can produce a more significant cumulative analgesic effect for primary dysmenorrhea patient than Xuanzhong and non-acupoint, and the effects of Xuanzhong and non-acupoit are equivalent.