To compare the effect of patient-controlled intravenous analgesia(PCIA) and superior inguinal ligament iliac fascia block combined with PCIA after hip replacement in the elderly. Total of 82 elderly patients were treated with hip arthroplasty from June 2019 to June 2021 and randomly divided into observation group and control group. There were 42 patients in control group, including 18 males and 24 females, aged from 60 to 78 years old with an average of (70.43±3.67) years old, 28 femoral neck fractures and 14 femoral head necrosis, who received PCIA. The study group consisted of 42 cases, including 20 males and 22 females, aged from 61 to 76 years old with an average of (69.68±3.74) years old, 25 femoral neck fractures and 17 femoral head necrosis, who received superior inguinal ligament iliac fascia block combined with PCIA. Pain visual analogue scale (VAS) and Ramesay sedation scores at 2 h, 6 h, 12 h, 24 h and 48 h after operation were evaluated. In addition, the follow-up results of the total consumption of sufentanil and the total number of PCIA compressions at 48 hours after operation, the first time of landing after surgery, the time of hospital stay, the incidence of adverse reactions, the satisfaction with analgesia of two groups were observed. All patients were followed up for 9 to 24 months with an average of(13.85±2.67) months. There was no significant difference in operation time and intraoperative bleeding between two groups (P>0.05). There was no difference in VAS between two groups at 2 hours after operation (P>0.05), and the VAS of the study group at 6 h, 12 h, 24 h and 48 h after operation were lower than those of the control group(P<0.05). The Ramesay sedation scores of the study group at 2 h, 6 h and 12 h after operation were higher than those of the control group(P<0.05), and there were no differences in Ramesay score between two groups at 24 h and 48 h after operation (P>0.05). The consumption of sufentanil in the study group within 48 hours after operation was lower than that in the control group (P<0.05), and PCIA compression times were lower than those in the control group(P<0.05), and the time of first landing was earlier than that in the control group(P<0.05). There was no significant difference in hospital stay, adverse reaction rate, complications between two groups (P>0.05). The satisfaction of analgesia in the study group was higher than that in the control group (P<0.05). Superior iliac fascia block of inguinal ligament combined with PCIA has significant analgesic and sedative effects after hip arthroplasty in the elderly. It can reduce the amount of sufentanil used and the total number of PCIA compressions, which is conducive to the early activity of patients out of bed, improve the satisfaction of analgesia.