Ｏｂｊｅｃｔｉｖｅ　To study the safety and feasibility of dexmedetomidine(Dex) combined with propofol target-controlled infusion(TCI) for sedation during fiberoptic bronchoscopy(FOB)-assisted nasotracheal intubation.　Methods　One hundred and forty-three ASA gradeⅠ, Ⅱ patients underwent general anesthesia for oral cancer surgery, aged 18-65 years with body mass index of 18-30 kg/m2, were randomly assigned into propofol TCI group (group P, n=65) or Dex group (group D, n=78). All Patients received fentanyl 1.5 μg/kg after entering the operating room, followed by propofol TCI with the initial target plasma concentration (Cp) 1.0 mg/L which was adjusted according to BIS, group D received Dex(0.5 μg/kg, 10 min) at the same time. 2% tetracaine 2.5 ml was injected into tracheal through cricothyroid membrane and naso-pharyngeal membrane was infiltrated with 1% tetracaine 2 ml for topical anesthesia in both groups until BIS value fell to 85. When the BIS value was between 80 and 70, FOB was loaded, once it passed the glottis， then the tracheal tube was placed, patients in both groups were administrated propofol 1 mg/kg in the meantime. General anesthesia was commenced after the nasotracheal tube was secured. The intraoperative and postoperative events including HR, MAP, SpO2 and BIS were recorded at five time points: patients arrived at the operating room(T0), BIS value fell to 85(T1), after the cricothyroid membrane puncture(T2), BIS value was between 80-70(T3), after the FOB placement(T4) and after the tracheal intubation (T5). Meanwhile propofol effect-site concentrations (Ce) at the time of T1 and T3 were recorded respectively.　Results　There were no significant differences between the two groups in the difficulty of intubation, tracheal intubation time, incidence of cough or aspiration (P>0.05). Compared with group P, airway obstruction score was significantly increased (48/7/20/3/0 vs 45/16/4/0/0), patients were more comfortable(62/16/0/0/0 vs 35/29/0/1/0), pain recall score was significantly increased(60/18/0 vs 62/3/0), postoperative sore throat score was significantly increased(22/55/1/0 vs 41/20/4/0) in group D. However, hemodynamic changes were better in group D(P<0.05). On the other hand, we found no significant differences in the propofol Ce mean at T1(P>0.05), but the propofol Ce mean at T3 were significantly decreased[(1.00±0.20) mg/L vs (1.10±0.30) mg/L] in group D compared with group P(P<0.05) .　Conclusions　The infusion of Dex(0.5 μg/kg, 10 min) used to supplement the topical anesthesia for FOB-assisted nasotracheal intubation decreased the propofol Ce for sedation and made patients more comfortable, but the complications such as airway obstruction, recall of the procedure and sore throat need to be considered.