Abstract: Objective : To assess the analgesic and ataractic efficacy and the side effect of sufentanil for postoperative self-controlled infusion analgesia (PSCIA) in the patient with thoracic surgery. Methods : A total of 40 patients (ASA I~Ⅱ)with selective thoracic surgery were equally randomized to receive 100ml of the analgesic regiments containing either sufentanil 200ug (group SF, n=20) or fentanyl 2mg (group F, n=20) for 72 hours. The postoperative self-controlled infusion analgesia was performed with the basal infusion rate of 1.0ml/h, bolus 1.0ml and locking time 15 minutes. Results :There was a satisfactory analgesia rate in each group, the analgesic result in more than 90 percent of patients was very good or good (P>0.05). But group SF got significantly lower pain-relief scores (YAS) in both resting and moving states at 8, 12, 24, 48, 72 h compared to group F (P<0.05). There was no significant difference between the groups in YAS at 4 h after surgery (P >0.05). Significantly higher SS scores were observed in group SF than in group F. No statistical difference was observed in the adverse reactions between two groups. Conclusion : PSCIA with sufentanil in thoracic surgery can achieve satisfactory analgesia and suitable sedation without more incidence of adverse reactions, such as dyspnea, nausea,vomiting. It seems that the analgesic potency of sufentanil is tenfold as strong as that of fentanyl, or even stronger.