Objective: To explore the effect of electro-acupuncture (EA) on glucose and lipid metabolism in unmarried patients with polycystic ovary syndrome (PCOS). Methods: Fifty-four PCOS patients were equally randomized into true acupuncture group and sham acupuncture group (control) for totally 16 weeks of treatment by random method with a computerized randomization program. Patients in true acupuncture group accepted traditional acupuncture methods with EA and two sets of acupoint groups were used alternatively. The first set consisted of Zhongji (CV 3), Qihai (CV 6), Guilai (ST 29), Sanyinjiao (SP 6), Yinlingquan (SP 9), Hegu (LI4) and Baihui (GV 20), and the second set consisted of Tianshu (ST 25), ST 29, CV 3, CV 6, SP 6, Taichong (LR 3), Neiguan (PC) 6 and GV 20. Patients in the sham acupuncture group accepted shallow acupuncture methods through EA without electricity at 4 non-meridian points in each shoulder and upper arm. Outcome measures included body mass index (BMI), waist-hip-ratio (WHR), oral glucose tolerance test (OGTT), insulin release test, glucose and lipid metabolism indicators such as total cholesterol (TC), triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, adiponectin, leptin, visfatin, resistin, and interleukin (IL-6). Results: Twenty-six subjects in the true acupuncture group and 20 subjects in the sham group completed the clinical trial. After 16 weeks of treatment, no significant difference in the outcome measures were observed between the two groups (P>0.05). However, as compared with baseline data, a reduction in weight, BMI, hipline, WHR, fasting glucose, homeostatic model assessment of insulin sensitivity, visfatin and HDL-C, and an increase in resistin and IL-6 were observed in the true acupuncture group (P<0.05). In addition, a reduction in visfatin and an increase in TC were also observed in the sham group (P<0.05). Conclusions: Acupuncture may have a beneficial effect in the treatment of PCOS by improving glucose and lipid metabolism. Moreover, the sham acupuncture may be not completely ineffective. Sham acupuncture may improve some of the aspects of the glucose and lipid metabolism of PCOS patients through a placebo effect.