Abstract: Objective To investigate the application effect of dexmedetomidine in pediatric fiberoptic bronchoscopy and alveolar lavage. Methods Sixty children electively undergoing bronchoscopy and alveolar lavage were randomly divided into observation group and control group, with 30 cases in each group. Children of both groups were given general anesthesia, the observation group was treated by dexmedetomidine, while the control group was given saline. The changes of vital signs of the two groups were observed. Mean blood pressure(MAP), heart rate(HR)and respiratory rate(RR)were recorded and analyzed at the time points of room entry(T₀), at the beginning of surgery(T₁), at time of laryngeal mask removal(T₂), at 5 min after laryngeal mask removal(T₃), at 15 min after laryngeal mask removal(T₄), and at 30 min after laryngeal mask removal(T₅). The operation time, anaesthesia time, duration from drug withdrawal to awakening, removal time of laryngeal mask, restlessness score and Ramsay sedative score were observed in the two groups. The perioperative adverse reactions such as laryngeal spasm, choking cough, nausea and vomiting were also recorded. Results There were no significant differences in HR and RR between the two groups(P>0.05). MAP and HR in the observation group at T₂, T₃ T₄ and T₅ were lower than those in the control group(P<0.05). There was no significant difference in duration from drug withdrawal after surgery conclusion to removal of laryngeal mask in two groups(P>0.05). After extubation, restlessness score and Ramsay sedation score in the observation group were better than that in the control group(P<0.05). In the observation group, the patients with restlessness and duration of restlessness lasting more than 15 minutes were - significantly less than those in the control group(P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups(P>0.05). Conclusion Dexmedetomidine applied in pediatric fiberoptic bronchoscopy and alveolar lavage can improve sedative effect during and after surgery, and patients have less adverse reactions.