Objective To analyze the effect of bispectral index monitoring anesthesia in elderly patients undergoing orthopedic surgery.Methods A total of 86 elderly patients with orthopedic surgery admitted to Changshu Hospital Affiliated to Soochow University from January 2020 to December 2021 were selected as the research objects.They were randomly divided into the conventional group(n=43)and the experimental group(n=43)by touching red and blue balls.Patients in the conventional group were adjusted according to the clinical work experience of anesthesiologists and patients'own conditions,while patients in the experimental group were added to the conventional group with dual-frequency index to fine-adjust the depth of anesthesia.The postoperative extubation time,recovery time,sedation before anesthesia,30 min after operation,and at the completion of operation,heart rate,mini-mental state examination (MMSE) score 24 h before operation,24 h after operation,and 72 h after operation,and the incidence of delirium were compared between the two groups.Results The extubation time and recovery time of the experimental group were shorter than those of the conventional group,and the differences were statistically significant (P＜0.05).The sedation scores at 30 min and the completion of operation in the experimental group were lower than those in the conventional group,and the differences were statistically significant (P＜0.05).The heart rate of patients in the experimental group at 30 min after operation and at the completion of operation were lower than those in the conventional group,and the differences were statistically significant (P＜0.05).The occurrence rate of postoperative delirium in the experimental group was lower than that in the conventional group,and the difference was statistically significant (P＜0.05).The MMSE scores of the experimental group at 24 and 72 h after operation were higher than those of the conventional group,and the differences were statistically significant (P＜0.05).Conclusion Bispectral index monitoring and adjustment of anesthesia in elderly patients undergoing orthopedic surgery can shorten the time of postoperative extubation and recovery,maintain the stability of heart rate,improve the abnormal cognitive function,obtain effective sedation,and reduce delirium.