Objective To evaluate the effect of inguinal iliac fascia block combined with general anesthesia on sign fluctuations and postoperative delirium in elderly patients undergoing hip arthroplasty. Methods The study was conducted among 126 elderly patients who underwent hip replacement surgery from March 2020 to December 2022. They were randomly divided into a control group and an observation group using random number table method, with 63 patients in each group. The control group received routine general anesthesia, while the observation group received inguinal iliac fascia block combined with general anesthesia. Vital sign indicators [heart rate （HR）, mean arterial pressure （MAP）] at entry （T₀）, intravenous infusion （T₁）, and intraoperative 30 min （T₂）, preoperative and postoperative C-reactive protein （CRP）, postoperative consciousness status [confusion assessment method （CAM-CR）], delirium occurrence, and adverse reactions were compared between the two groups. Results The HR and MAP at T₁ in the observation group were higher than those in the control group, while the HR and MAP at T₂ were lower （P<0.05）. The postoperative CRP in the observation group was lower than that in the control group （P<0.05）. The CAM-CR score and the incidence rate of delirium of the observation group were lower than those of the control group （P<0.05）. There was no significant difference in the incidence of adverse reactions between the two groups （P>0.05）. Conclusion The use of inguinal iliac fascia block combined with general anesthesia can effectively prevent postoperative delirium in elderly patients undergoing hip arthroplasty.