Abstract: Objective To explore the influence of dexmedetomidines medicated at different times on tracheal extubation in patients with general anesthesia.Methods 80 patients with general anesthesia were selected and randomly divided into observation group and control group,40 cases in each group.The observation group was intravenously pumped with 0.6 μg /kg of dexmedetomidine 3 0 minutes before anesthesia induction ,while the control group was intravenously pumped with 0.6 μg /kg of dexmedetomidine at the end of surgeries.The hemodynamic indexes,restlessness and adverse reactions were observed at different time points.Results At the time of extubation (T1), the heart disease rate (HR)and mean artery pressure (MAP)levels in both groups were higher than the baseline values before surgeries (T0)(P >0.05).In 5 minutes after extubation,HR and MAP started to decrease gradually,at 60 minutes after extubation (T6),HR and MAP decreased to val-ues near to those at T0(P >0.05).There were no significant differences of HR and MAP,SpO2, palinesthesia time,restlessness incidence and adverse reaction from T0 to T6 between two groups (P >0.05).The extubation time of the control group was significantly longer than that of the ob-servation group (P <0.05).Conclusion Perioperative application of dexmedetomidine can effec-tively inhibit HR increase and blood pressure elevation caused by tracheal extubation,without caus-ing insignificant respiratory depression effects,but application at the end of surgeries can prolong extubation time,thus,application before anesthesia induction is a better choice.