Ｏｂｊｅｃｔｉｖｅ　To compare the postoperative analgesic effects of ultrasound-guided thoracic paravertebral block with concentrations of ropivacaine on patients received thoracotomy.　Methods　Sixty-nine patients undergoing thoracotomy were randomly divided into three groups(n=23), respectively received high (group H, 0.375%), medium (group M, 0.25%), and low (group L, 0.15%) concentrations of ropivacaine. After operation, all patients received thoracic paravertebral blockade under the guidance of ultrasound. VAS during rest, coughing, and deep breath, were recorded.　Results　Compared with group L, the VAS during rest significantly decreased in group H and M (P<0.05) immediately after patients entered the PACU. Furthermore, the VAS scores during rest, coughing, and deep breath in group H and M 6 h after operations declined significantly more than those in group L(P<0.05).　Conclusions　Ultrasound-guided thoracic paravertebral blockade with 20 ml 0.25% ropivacaine provided satisfying postoperative analgesic effects on patients received thoracotomy.