Abstract: Objective: To compare the anesthetic effect of anesthsia epidural block with different concentrations of ropivacaine on elderly patients receiving thoracic surgery.Methods: Forty-five patients receiving thoracic surgery were randomly divided into normal saline group(group A),0.25% ropivacaine group(group B) and 0.5% ropivacaine group(group C),with 15 cases in each.After induction of anesthesia,group B and group C were injected 5 ml ropivacaine of corresponding concentration every 60 min to the epidural cavity,and group A were injected 5 ml saline.The MAP,HR,the time of breathing recovery,opening eyes,extubation and the side effects after anesthesia were recorded.Results: HR and MAP decreased in all the three groups after anesthesia induction(P<0.05 to P<0.01).After tracheal intubation,the HR and MAP increased significantly in group A(P<0.01),fluctuated mildly in group B(P>0.05) and decreased greatly in group C.The time of breathing recovery,opening eyes and extubation in group A was significantly longer than that in group B and group C(P<0.01),and there was no obvious difference between group B and group C(P>0.05).No nausea,vomiting or respiratory depression were observed during the operation in all the three groups.One patient in group A presented irritability.Conclusions: 0.25% ropivacaine epidural anesthesia combined with general anesthesia can be safely and effectively used in elderly patients undergoing thoracic surgery.