【Abstract】 Objective To evaluate the efficacy and safety of dexmedetomidine used for postoperative intravenous analgesia in patients with large-area burn. Methods Forty 18-60 years old patients, undergoing escharectomy were randomly assigned into two groups with 20 cases each. Group I received PCIA with fentanyl; Group Ⅱreceived PCIA with dexmedetomidine and fentanyl. VAS scores and Ramsay scores at 4、8、24 and 48h after operation and the incidence of nausea and vomit、somnolence、bradycardia and respiratory depression were recorded. The satisfactory degree of patients was recorded at 48h.Results Compared with Group I, the VAS score of Group Ⅱ at any time point and the incidence of nausea and vomit in Group Ⅱwere significantly decreased. There was no significant difference in the incidence of somnolence、bradycardia 、respiratory depression and Ramsay score between the two groups. The satisfactory degree of patients in Group Ⅱ(95%) was obviously higher than that in Group I (65%，P<0.05) at 48h. Conclusion The application of dexmedetomidine coupled with fentanyl in PCIA can result in satisfactory effect of analgesia and sedation and decrease the incidence of nausea and vomit significantly, which will do more good to the patients with large-area burn. 【Key words】 burn; postoperative intravenous analgesia; dexmedetomidine ;fentanyl