【Abstract】 Objective To determine the effect of oxycodone on emergence pain after intravenous remifentanil anesthesia in elderly patients with laparoscopic resection of gallbladder.Methods Thirty-two ASAⅠorⅡ patients,aged 65-74 years undergoing laparoscopic resection of gallbladder under general anesthesia were studied.Anesthesia was induced with etomidate 0.3mg/kg,then administrated remifentanil with the Minto model of TCI to the concentration of 3.0ng/ml.When the numerical value of BIS was 40 to 45 we used cisatracurium 0.2mg/kg and completed intubation and mechanical ventilation in 5 minutes. Besides remifentanil, no other analgesic drugs were added. Anesthesia was maintained with propofol and remifentanil by the model of TCI which were terminated at the end of surgery.Oxycodone was injected 5 minutes before the end of surgery by using modified Dixon’s up-and-down method.VAS scores≥4 was defined as postoperative acute pain.ED50 and 95% confidence interval (CI) of oxycodone on postoperative acute pain were calculated.The time of total operation ,extubation after operation and side effects such as nausea and vomiting were recorded.Results ED50 was 0.126mg/kg.95%CI was 0.093～0.181mg/kg.Conclusion The ED50 and 95%CI of oxycodone for inhibition of acute pain after intravenous remifentanil anesthesia in elderly patients undergoing laparoscopic resection of gallbladder were 0.126mg/kg and 0.093～0.181mg/kg respectively.