To evaluate and explore the mechanism of the effect of hypertonic pre-injection on postoperative delirium in the aged. From June 2016 to February 2017, participants scheduled hip arthroplasty surgery were randomly divided into four groups: Group 1 (H1) 30 patients pre-injected 4 ml/kg hypertonic solution were proceeded general anesthesia; Group 2 (H2) 30 patients pre-injected 4 ml/kg hypertonic solution were proceeded spinal canal anesthesia; Group 3 (C1) 30 patients pre-injected 4 ml/kg isotonic saline were proceeded general anesthesia; Group 4 (C2) 30 patients pre-injected 4 ml/kg isotonic saline were proceeded spinal canal anesthesia in Department of Anesthesiology, Third Hospital of Hebei Medical University.All these patients were operated after anesthesia.To avoid electrolyte disorder, the level of Na(+) , Ca(2+) , K(+) in the artery blood was analyzed.Peripheral venous blood was extracted to detect the concentration of inflammatory factors IL-1β, IL-6, IL-10, TNF-α and nerve injury factor S100β.In order