Abstract: Objective：To explore the pain profile following ultrasound guided single shot peripheral nerve blocks (sPNBs) anesthesia and investigate risk factors for rebound pain. Methods：Patients scheduled for orthopedic surgery under ultrasound guided sPNBs anesthesia were selected. The patients were followed up 24 h and 48 h after the block. The numeric rating scale (NRS) score, onset time, characteristics, pain-relief approach of peak pain, and sleep quality on the operation day were recorded. Results：A total of 31 patients aged 22-83 years old were included. There were 25 patients (80.6%) with moderate to severe pain levels (NRS≥4), 15 (48.4%) of whom reached severe pain level (NRS≥7). Those who with moderate to severe pain described the pain as suddenly onset, poorly controlled by sulfentanil administration, and resolved after 30 min to 1 h. The median occurrence time of peak pain was 16.8 h (IQR 12.3-22.9). The rebound pain was less pronounced in patients >60 years old (P<0.05). The later the pain occurred, the lower the NRS score was (P<0.05). sPNBs administration alone was the risk factor for rebound pain. Conclusions：The incidence of moderate to severe pain after orthopedic surgery undergoing ultrasound-guided sPNBs anesthesia is high, and the incidence of patients ≤60 years old is higher than that of patients over 60 years old. Rebound pain occurs in 12-24 h after the block, and the degree of pain decreases with the delay of the time. Patients who have PNBs anesthesia alone are more prone to rebound pain than those who have combined anesthesia.