Abstract: Objective To explore the safety and effectiveness of Dexmedetomidine(Dex) at different doses used in laparoscopic partial hepatectomy. Methods A total of 60 patients (ASA Ⅱ or Ⅲ magnitude) who received elective laparoscopic partial hepatectomy were randomly divided into Group D1 and Group D2.Group D1 received vein pump injection dose of Dex load 0.2 μg/kg (10 min after injection), and was followed by pump injection of 0.2 μg/(kg·h) for 30 min before the end of surgery. Group D2 received vein pump injection dose of Dex load 0.2 μg/kg (10 min after injection), and was followed by pump injection of 0.5 μg/(kg·h) for 30 min before the end of surgery. The patients in two groups were both given sevoflurane and propofol to maintain anesthesia in surgery and observed and recorded systolic and diastolic pressure,heart rate,oxygen saturation of blood,postoperative respiratory recovery time, eye-opening time, extubation time and the number of agitation before infusion with Dexmedetomidine (T0), at 10 minutes after infusion of Dexmedetomidine (T1), endotracheal intubation immediately (T2), 1 min after endotracheal intubation(T3), and endotracheal tube being drawn immediately (T4).Results Comparing with those at the time of entering the operation room, blood pressure and heart rate in the two groups before and after intubation and at the extubation time were not significantly different (P>0.05). The respiratorg recovery time,eye-opening time and extubation time of group D2 were longer than those of group D1(P<0.05).Conclusion With maintained pump infusion of Dex at dose of 0.2 μg/(kg·h),patients undergoing laparoscopic partial hepatectomy have more stable hemodynamics and revive more quickly and completely after operation.