Objective: To investigate the analgesic efficacy of ultrasound guided thoracic paravertebral block during open pancreaticoduodenectomy (PD). Methods: Forty three patients scheduled for an elective open PD were randomly designated to control group (21 cases) and observation group (22 cases). Patients in control group underwent general anesthesia alone, and those in observation group underwent ultrasound guided paravertrbral block through injection of 10 mL of 0.4% ropivacaine each at right T8–9 and T11–12 interspaces 20 min before general anesthesia induction. Patient controlled intravenous analgesia (PCIA) was used in all patients after operation. Several variables were recorded, including the mean artery pressure (MAP) and heart rate (HR) at the times of just after entering the operation room, before skin incision, 5 min after skin incision and shortly before the end of operation, the amount of intraoperative sulfentanil consumption, PCIA compress frequency within 48 h after operation, the visual analogue score (VAS) both during resting state and 90° body turning over at 2, 16, 24 and 48 h after operation, and the occurrence of adverse reactions. Results: There were no differences in baseline data between the two groups of patients (all P>0.05). In observation group compared with control group, the average MAP (83 mmHg vs. 95 mmHg) and HR (77 beats/min vs. 87 beats/min) at 5 min after skin incision were significantly decreased (both P<0.05), but showed no significant difference at the other 3 time points (all P>0.05), the average VAS scores at resting state and 90° body turning over were significantly reduced at 2, 16 and 24 h after operation (all P<0.05), but showed no significant differences at 48 h after operation (both P>0.05), and the average amount of intraoperative sulfentanil consumption (0.9 μg/kg vs. 1.5 μg/kg) and PCIA requirements (13.1 times vs. 27.6 times) were significantly decreased (both P<0.05). No significant differences were noted in the adverse reactions such as postoperative nausea, vomiting, sweating, dizziness, itching and delirium between the two groups (all P>0.05), and no respiratory depression occurred in either group. Conclusion: Ultrasound guided thoracic paravertebral block provides a remarkable pain relief effect for patients during and after open PD.