Abstract: ob＜x＞jective To evaluate the effect of low dose s-ketamine on the quality of emergence in patients undergoing transnasal transsphenoidal pituitary tumor resection. Methods Sixty patients for selective transnasal transsphenoidal pituitary tumor resection under intravenous general anesthesia,were randomly divided into group s-ketamine（group R, n = 30）and control group (group S, n = 30）.Group R was given 0.15 mg/kg s-ketamine intravenously after induction of general anesthesia and continued at a pump rate of 5ug/kg/min until 15 min before the end of the operation, and group S with saline. The incidence and severity of coughing,agitation and pain during the recovery period from general anesthesia , the hemodynamic changes during extubation ,the eye?opening time,extubation time and adverse events in the post-anesthesia care unit (PACU) were recorded and analyzed. Results Compared with group S，the incidence and severity of coughing, moderate and severe pain were significantly decreased during the recovery period from anesthesia in group R（P < 0.05）. The mean arterial pressure and heart rate in group R during extubation were significantly lower than those in group S（P < 0.05）. There was no significant difference of the incidence of agitation, the eye?opening time , extubation time and the adverse events between two groups（P>0.05）. Conclusion In transnasal transsphenoidal pituitary tumor resection, continuous infusion of low dose s-ketamine can reduce the incidence and severity of cough during recovery, reduce postoperative pain, maintain hemodynamic stability during extubation, and doesn’t prolong the recovery time and doesn’t increase the adverse events,which is beneficial to improve the quality of emergence of patients.