Object: To explore the mechanism of the electro-acupuncture (EA) induced sedation effect in general anaesthesia through investigating the role of the Benzodiazepines-GABA system. Method: 80 patients undergoing abdominal surgery were randomly divided into four groups (n=20): C group (propofol only group),F group (propofol + flumazenil group),EA group (propofol + electro-acupuncture group),and EA+F group (propofol + electro-acupuncture + flumazenil group). Before induction,acupuncture needles were inserted at the points of Zusanli (ST 36) and Neiguan (PC 6) bilaterally to elicit"DeQi". Target-controlled infusion (TCI) of propofol was used for the induction and maintenance of anaesthesia. After 15minutes,equilibrium of Narcotrend Index (NT index) was achieved,patients were then assigned to receive different interventions. In EA group and EA+F group,patients received EA for 30 minutes under general anaesthesia,and flumazenil with the dosage of 0.1mg/kg was added in the latter at the end of EA. In C group and F group,patients didn't receive EA,and flumazenil with the dosage of 0.1mg/kg was administered in F Group at the same time point with EA+F group. HR,MAP and NT index were recorded at different time points up to 30 minutes after the end of EA.