Background　The over?蛳excitation of sympathetic system caused by any stimulus in perioperative period will influence seriously in organ function and homeostasis of internal environment. To relieve the stress, several drugs usually be applied to control the excessive excitement in nervous system.　Objective　Parasympathetic nervous system, as one part of the autonomic nervous system, especially vagus nerve always suffers seriously in activity while the inhibition of sympathetic system occurred. It may cause multiple organ malfunction subsequently.　Content　It focuses on the vagus nerve, as the main functional undertaker in parasympathetic system, acts an important role in basic regulation of organ function in pleuroperitoneal cavity and homeostasis of internal environment.　Trend　In order to avoid the neglect of parasympathetic system in regulating organ function during perioperative period, it is necessary to gives advices and opinions in the protection of vagus nerve while inhibiting super?蛳excitation of sympathetic system.