 A total of 160 eligible patients will be included in this trial and randomly assigned to experimental group and control group in a 1:1 ratio. In experimental group, selected acupoints will be stimulated by the new intelligent electro-acupuncture instrument; while for control group, electroacupuncture treatment will be accomplished by a pre-existing electro-acupuncture instrument. The duration of treatment will be 2 weeks. The primary outcome is the change of visual analog scale score after one course of treatment. The secondary outcomes are visual analog scale score after each treatment, the responder rate, drug-usage rate of non-steroidal antipyretic analgesics, the occurrence rate of adverse events, defect rate of instrument, and excellent rate of instrument. 