BACKGROUND: Acu-point specificity is a key issue in acupuncture. To date there has not been any satisfactory trial which can ratify the specific effect of acupuncture. This trial will evaluate the specific effect of BL33 for mild and moderate benign prostatic hyperplasia (BPH) on the basis of its effectiveness. The non-specific effect will be excluded and the therapeutic effect will be evaluated. METHOD: This is a double-blinded randomized controlled trial. 100 Patients will be randomly allocated into the treatment group (n = 50) and the control group (n = 50). The treatment group receives needling at BL33 and the control group receives needling at non-point. The needling depth, angle, direction, achievement of De Qi and parameters of electroacupuncture are exactly the same in both groups. The primary outcome measure is reduction of international prostate symptom score (IPSS) at the 6th week and the secondary outcome measures are reduction of bladder residual urine, increase in maximum urinary flow rate at the 6th week and reduction of IPSS at the 18th week. DISCUSSION: This trial will assess the specific therapeutic effect of electroacupuncture at BL33 for mild and moderate BPH. TRIAL REGISTRATION: Protocol Registration System of Clinical Trials.gov NCT01218243.