Background: Cancer-related pain is one of the primary symptoms of patients with hepatocellular carcinoma (HCC). Previous studies have shown that transcutaneous electrical acupoint stimulation (TEAS) is effective in treating patients with acute or chronic pain. In China, it is indispensable to evaluate the efficacy of TEAS in combination with opioids for the treatment of moderate to severe HCC-related pain. Methods/Design: This is a single-center clinical, prospective randomized controlled clinical trial protocol. 104 patients will be randomly divided into the observation group and the control group in a ratio of 1:1. In addition to routine cancer pain medication, the two groups of patients will receive TEAS treatment twice a day for one week. Acupoints will include bilateral Hegu(LI4), Neiguan (PC6), Zusanli(ST36), Taichong(LR3), Ganshu(BL18), Geshu(BL17), Qimen(LR14), and Zhangmen(LR13). The treatment time is from 9:00 a.m. to 11:00 p.m. and from 4:00 p.m. to 6:00 p.m. The primary outcome measures are the Numerical Rating Scale (NRS) and the secondary outcome measures include the Brief Pain Inventory(BPI), dosage and administration duration of opioid drugs, frequency of nausea, vomiting and defecation, Karnofsky Performance Status Scale (KPS), Quality of life scale (QOL), Brief Fatigue Inventory (BFI). The outcome measures will be evaluated at baseline, during treatment and 1 week after treatment. Discussion: Results of this trial are expected to clarify the value of TEAS stimulation performed on specific points in the management of moderate to severe pain in HCC. Trial registration: Chinese clinical trial registry, ChiCTR2100044615 ( Keywords: protocol, hepatocellular carcinoma, TEAS, pain