[Abstract] Objective To observe the effect of single dose dexmedetomine(Dex) on general anesthesia in laparoscpic cholecystectomy. Methods Fifty ASA Ⅰ or Ⅱ patients of both sexes aged 21-57 kg undergoing elective laparoscopic cholecystectomy were randomly divided into 2 groups (n=25 each):dexmedetomine group and control group. Group C (control) received normal saline 10ml and the whole dose was given within 10 minutes. Group D received equal volume of Dex 0.6μg/kg intravenous injection as group C. MAP and HR were recorded at the time points of pre-administration of Dex(T0), 5min after administration(T1), before anesthesia induction(T2), 1 and 2 min after injecting propofol respectively(T3～4), immediately after intubation(T5), 1，3 and 5 min after intubation(T6～8). The following variables were also recorded: duration induction，duration of anesthesia and operation，extubation time，regain consciousness time，coughing when extubating，dosage of propofol or sufentanyl， frequency of cardioactive drug. Results The duration of induction was significantly shorter（P<0.01）, coughing when extubating was decreased（P<0.05）,and the requirements of propofol or sufentanyl were decrased（P<0.01）, but the requirement of atropine was increased in group D than in group C（P<0.05）. Compared with T0 or every time points of group D, MAP was significantly decreased at T3～8 in group C（P<0.05）. MAP was significantly higher in group D at T1（P<0.05）. HR was significantly low in group C at T4 and T5（P<0.05）. In addition, HR was significantly low in group D at T1～8（P<0.05）,and was significantly low in group D than in group C at T1～3 and T6～8（P<0.05）. Conclusion A single dose of Dex given intravenously before induction is beneficial to patients in laparoscopic cholecystectomy. [Key words] dexmedetomidine; laparoscopic cholecystectomy; general anesthesia