Objective To evaluate the advantage of pericapsular hip nerve block (PENGB) combined with unilateral lumbar anesthesia in elderly patients undergoing total hip replacement.Methods A total of 74 elderly patients who were scheduled for THA were enrolled. Random number table method was used to divide them into two groups (n=37): group P was the pericapsular nerve block of hip joint(PENGB) guided by ultrasound,while group F was the ultrasound-guided iliofascial space block (FICB) group. Unilateral lumbar anesthesia was performed in both groups. Static and dynamic NRS scores were recorded before nerve block (T0), 5 minutes (T1), 15 minutes (T2), and 30 minutes (T3) after nerve block, and 6 hours (T4), 12 hours (T5), and 24 hours (T6) after surgery; the first postoperative analgesic pump compression time, the number of effective compressions within 24h, the total dosage of sufentanil, the number of relief analgesia cases and the satisfaction of patients with analgesia were recorded; quadriceps muscle strength at T4, T5, and T6 were recorded, as well as the patient's first postoperative walking time, first postoperative walking distance, and postoperative hospital stay; Pittsburgh Sleep Quality Index (PSQI) scores 1 day before surgery and 1, 3, 7 and 30 days after surgery and the incidence of adverse reactions 24h after surgery were compared between the two groups.Results The resting and dynamic NRS scores in group P were lower than those in group F (P0.05). Compared with group F, the first postoperative analgesic pump compression time was prolonged in group P, the effective pressing times of analgesic pump within 24h was reduced, the total dosage of sufentanil was decreased, patients' satisfaction with analgesia was increased, the first time to get out of bed and the length of hospital stay were shortened, and the first walking distance was prolonged(P0.05). The strength of quadriceps muscle in group P was higher than that in group F(P0.05). The PSQI scores of group P 1 day, 3 day and 7 day after surgery were lower than those of group F(P0.05). There was no statistical significance in the occurrence of adverse reactions between the two groups (P0.05). Conclusion Ultrasound-guided peripheral hip capsule nerve block combined with unilateral lumbar anesthesia has significant analgesic effect after THA in the elderly, and is helpful to improve postoperative sleep quality and promote early postoperative recovery.