Objective To observe the effect of ultrasound-guided single erector spinae plane (ESP ) block combined with patient-controlled intravenous analgesia (PCIA ) on postoperative analgesia in patients undergoing lobectomy performed via video-assisted thoracoscope. Methods Forty patients (20 males and 20 females,ASA physical status Ⅰ or Ⅱ),scheduled for e-lective video-assisted thoracoscopic lobectomy,were randomly assigned into two groups,ESP block combined with PCIA group (group EP)and PCIA only group (group P).ESP block was given to pa-tients in group EP before operation,and its effect was evaluated by testing the area of block.VAS scores were recorded at 1,6,18,24 and 48 h after operation.The frequency for compress PCIA,the volume of analgesic drugs,the consumption of flurbiprofen axetil and the side-effects were recorded as well.Results ESP block was accomplished in group EP with sensory loss from T2-T8 or T3-T7 over the entire posterolateral aspect of the hemithorax.And there were no puncture-related complications. The VAS scores both at rest and coughing in group EP were lower than those in group P (P <0.05). The compress PCA numbers,the volume of analgesic drugs and the consumption of flurbiprofen axetil were significantly less in group EP than those in group P (P <0.05).Only nausea and vomiting were observed as postoperative side effects,and there were no significant differences between the two groups.Conclusion Ultrasound-guided single erector spinae plane block combined with PCIA is a sa-fer and more effective method for the analgesia of thoracic operation than PCIA only.