This study is a prospective, randomized, controlled trial.The selected patients were randomly divided into remazolam general anesthesia group and propofol + midazolam general anesthesia control group according to computer randomization method. There were 65 patients in each group. Remazolam general anesthesia group (R group): Remazolam 0.4 mg/kg for rapid induction of loss of consciousness for anesthesia induction and 1 mg/kg/h for maintenance. Propofol + midazolam general anesthesia control group (group P): propofol 1.5 mg/kg + midazolam 0.05 mg/kg slow intravenous push until the patient's consciousness disappeared, then propofol 4-8 mg/kg/h Anesthesia was maintained. Except for different sedative drugs, the analgesic and muscle relaxant medication regimens were the same between the two groups. In the study, the application of inhaled anesthetics, other benzodiazepines and anticholinergic drugs was restricted, and the mean arterial pressure during the operation was kept above 60 mmHg to avoid perioperative hypotension, hypoxemia, and hypercapnia. Warm measures were used to maintain the patient's intraoperative body temperature above 36.0 °C. POD assessment was performed on the day before surgery and on days 1-7 after surgery.

Inclusion Criteria:

• Elderly patients with limited abdominal tumor surgery (age ≥65 years)
• ASA classification I-III.

Exclusion Criteria:

• Refusing to participate in the study
• Patients with severe arrhythmia or cardiac dysfunction (EF<35%)
• A clear history of neurological and psychiatric disorders before surgery or long-term use of sedatives or antidepressants
• History of alcoholism or drug dependence
• History of brain surgery or trauma
• Severe vision or hearing impairment
• Inability to cooperate with the completion of cognitive function tests