【Abstract】Objective　To investigate the safety and efficacy of dexmedetomidine in Single-balloon enteroscopy. Methods　thirty patients ASA gradeⅠorⅡ, scheduled for Single-balloon enteroscopy were randomly assigned to two groups: group D ( intravenous perfusion of dexmedetomidine 0.6μg/kg),group C (normal saline of equal volume with dexmedetomidine )，each group had fifteen cases. Group D and group C respectively received dexmedetomidine and normal saline before induction by ways of intravenous infusion (the duration of infusion was ten minutes). Then general anesthesia was induct-ed by perfusion of propofol，intravenous injection of fentanyl and vecuronium..The maintainence of anesthesia used by propofol intravenous injection in both two groups. Patients blood pressure, heart rate and spo2 were recorded at the time of entering the operating room, intravenous infusion after 10 minutes, intubation, insertion of Single-balloon enteroscopy and extubation. Results　Compared with group D, at the time of intubation, insertion of Single-balloon enteroscopy and extubation, the blood pressure and heart rate of group C were significantly increased (P<0.05). In group C, the blood pressure and heart rate at the time of intubation, insertion of Single-balloon enteroscopy and extubation were significantly increased compared with basic (P<0.05). Compared with group C，patients in group D falled sleep faster with significant lower dose of propofol (P<0.05). The time of anesthesia awake in group D was decreased significantly than in group C (P<0.05). Conclusion　Perfusion of dexmedetomidine with 0.6μg/kg for 10 minutes before induction presented more stable during the whole period of induction.，It also reduces the dosis of propofol in the period of induction. and operation. Dexmedetomidine can make patients hemodynamics more stable and the recovery more rapid and complete.