Objectives: The aim of this study was to examine the effect of electroacupuncture (EA) at an acupoint, HT8 (Sobu), on normal humans by using power spectral analysis. We examined the effect on the Heart Rate Variability (HRV), and the balance of the autonomic nervous system. Methods: Thirty-two healthy volunteers participated in this study. EEG (Electroencephalogram) power spectrum exhibits site-specific and state-related differences in specific frequency bands. A thirty-two channel EEG study was carried out on thirty-two subjects (14 males; mean age=23.5 years old, 18 females; mean age=21.5 years old). HRV and EEG were simultaneously recorded before and after acupuncture. Results: In the α(alpha) band, during the HT8-acupoint treatment, the power values in the α(alpha) band significantly decreased(p＜0.05) at 28 channels. In the β(beta) band significantly decreased(p＜ 0.05) at 26 channels. In δ(delta) band significantly decreased(p＜0.05) at 18 channels. In θ(theta) band significantly decreased(p＜ 0.05) at 20 channels. α/β values were increased at 6 channels and decreased at 10 channels. β/θ values were increased at 10 channels and decreased at 19 channels. Mean-RR(RR-interval), Complexity, RMSSD(Root mean square of successive differences), SDSD(Standard deviations differences between adjacent normal R-R intervals), norm HF showed a significantly increased and mean-HRV, norm LF, LHR(LF/HF Ratio) showed a significantly decreased after HT8-acupoint treatment(p＜0.05). Conclusions: These results suggest that EA at the HT8 mostly causes significant changes on alpha (28 channels), beta (26 channels), delta(18 channels), theta(20 channels) bands and mean-HRV, mean-RR, complexity, RMSSD, SDSD, norm LF, norm HF and LHR. If practicing EA at the HT8, it will regulate the function of the cerebral cortex, decrease activity of the sympathetic and increase parasympathetic nervous activity.