The effects of PFC stimulation on spontaneous and evoked discharges of neurons of parafascicular nucleus of thalamus were observed in rats. The results show that after PFC stimulation spontaneous of 78.7% PEN (48/61) and evoked discharges on noxious stimulation of 76.6% PEN (46/60) were decreased; spontaneous discharges of 72% PIN (18/25) were increased; inhibition response on noxious stimulation of 70.8% PIN (17/24) were decreased; and spontaneous discharges of 66.7% CON (6/9) and evoked discharges on noxious stimulation of 55.6% CON (5/9) were decreased. The results suggest that PFC might have analgesia action which was accomplished by modulating electric activities of pain-related neurons of parafascicular nucleus in thalamus.