Abstract: Objective To evaluate the safety of patient-controlled intravenous analgesia (PCIA) for elderly patient. Methods Forty adult thorax cancer patients after operation were divided into control group(42.6±6.9岁) and old group (67.8±4.7岁) according to their age.All patients received intravenous 0.6% Tramadol+0.0025% droperidoli mixture with LCP mode short-time (Loading dose:tramadol 50-100mg、Bolus 1ml and Continuous constant injection for 2ml/h to postoperative 12nd hours.after that,they are injected with Bolus mode only).Bp、HR and SpO2 were monitored for the first 24 hous following PCIA.The 24-hour injection dosage was recorded.The analgesia effects、untoward reactions were observed. Results The dosage of tramadol was 316.2±72mg in control group and 247.8±58mg in old group.Bp、HR didn't alter markedly in both groups throughout the whole period.RR and SpO2 were all within normal range. Conclusion With adequate dosage PCIA can be used safely for elderly patient postoperative analgesia.It can be avoid damnification of puncture for epidural analgesia.