Postoperative delirium has a higher incidence in elderly patients after general anesthesiaand It is closely related to the type of surgery, the length of surgery, and the patient's physique.Because head and neck maxillofacial radical surgery requires free flap transplantation and longer duration,and hemorrhage is more when the primary focus is removedIntraoperative blood pressure reduction is needed to reduce bleedingtherefore, hypoperfusion of craniocerebral blood flow will occur.Low cerebral perfusion is closely related to the occurrence of postoperative delirium.Patients undergoing this type of surgery have more preoperative complicationshypertension is particularly common.Therefore, this study mainly studied the correlation between the preoperative blood pressure level and the controlled hypotension level in patients with radical head and neck and maxillofacial tumors and the incidence of postoperative delirium.