Abstract: Objective 　The aim of this study was to evaluate analgesic efficacy of intercostal nerves block with ropivacaine for post2thoracotomy pain. Methods 　80 ASA physical status Ⅰ～ Ⅱpatient s undergo2 ing thoracotomy were randomly allocated into two groups, one to receive post2thoracotomy analgesia via intercostal nerves block with ropivacaine at the end of operation, the orther not receive intercostal nerves block. In the case of inadequate analgesia, morphine was used via patient2cont rolled analgesia ( PCA)pump, the variables recorded were the visual analogue scale (VAS), the number of bolus applications of morphine through PCA and the number of patient s undergoing bronchoscopy to resolve post2operation at2 electasis in each group . Results 　The postoperative pain cont rol during the first 482h period was satisfac2 tory with patient s who were administ rated with ropivacaine block, the number of bolus application of mor2 phine and the number of patient s needing bronchoscopy was much less than that in patient s who did not undergo ropivacaine block. Conclusion 　The intercostal nerve administ ration of ropivacaine provides satis2 factory pain cont rol af ter thoracotomy.