Abstract: Objective: To compare the hemodynamic variation,palinesthesia time and complications in using remifentanil or fentanyl as anesthetic in elderly patients receiving thoracic surgery.Methods: Eighty ASA Ⅰ-Ⅱ elderly patients undergoing thoracic surgery were randomly divided into remifentanil group(group R,n=40) and fentanyl group(group F,n=40).In addition to midazolam 0.05 mg/kg,vecuronium bromide 0.1 mg/kg and propofol 2 mg/kg,remifentanil 1 μg/kg was added to group R and fentanyl 3 μg/kg to group F.The anesthesia was maintained by isoflurance in group F and 0.1 μg·kg^-1·min^-1 remifentanil in group R.The systolic blood pressure,dystolic blood pressure and heart rate before induction,before and after intubation,at the time of cutting skin,removing costal bone,closing chest,and before and after extubation were recorded.The time of respiration recovery,eye opening,extubation and some side effects were also recorded.The patients' consciousness during operation and satisfaction degree were surveyed 24 h after operation.Results: Systolic blood pressure,dystolic blood pressure and heart rate had no statistic differences before induction,before and after intubation and at the time of cutting skin(P>0.05),but the difference was significant at the time of removing the costal bone and closing the chest(P<0.05).There was no statistic difference in analepsia time or complications between the two groups(P>0.05).Conclusions: Remifentanil-induced anesthesia may provide stable hemodynamics for elderly patients undergoing thoracic surgery.It is safe and effective.