Objective To compare the anesthesia effects of general anesthesia combined with and without single-injection of thoracic paravertebral nerve block (TPVB) for thoracotomy. Methods Forty patients undergoing thoracotomy were randomly divided into two groups: general anesthesia group (GA, n=20) and thoracic paravertebral nerve block combined with general anesthesia (TPVB+GA, n=20) group. In GA group, patients received endotracheal intubation after intravenous anesthesia induction. In TPVB+GA group, patients received single-injection of thoracic paravertebral nerve block before anesthesia induction, and the injection point was identified due to the operative incision. General anesthesia was induced 30 min later when TPVB was completed. Sevoflurane combined anesthesia was given during the operation, and end-tidal concentration maintained 1.0 MAC. Heart rate (HR) and blood pressure (BP) were maintained ±25% of base values. Comparisons were made between these two groups in the consumption of fentanyl and vasoconstrictor agents (ephedrine), pain grade evaluated visual analogue scale (VAS) of rest and movement at time points of 6, 12, 24, 36, 48 h after operation, the consumption of supplemental opioid (morphine) administration during the periods of 0-6 h (T_0-6), 6-12 h (T_6-12), 12-24 h (T_12-24), 24-36 h (T_24-36) and 36-48 h (T_36-48) after the operation and the rate of postoperative nausea and vomiting (PONV). Results The dosage of fentanyl during the operation was less in TPVB+GA group (P<0.05), and the counts of patients who need ephedrine was more in TPVB+GA group (P<0.05). VAS of rest and movement at time points of 6 and 12 h was lower in TPVB+GA group (P<0.05), however, there was no difference at time points of 24, 36 and 48 h between the two groups. The consumption of morphine during T_0-6 and T_6-12 was less in TPVB+GA group (P<0.05). However, there was no difference during T_12-24, T_24-36 and T_36-48 between the two groups. The rate of PONV was lower in TPVB+GA group (P<0.05). Conclusions TPVB can promote relief effect on pain, reduce VAS in the early period after thoracotomy, and decrease the dosage of opioid and the incidence of nausea and vomiting.