Inclusion Criteria:  Age 65 or above ASA-PSTYPE I or II Both male and female Laparoscopic radical gastrectomy for gastric cancer  Exclusion Criteria:  The patient had abnormal liver, kidney and other important organs before surgery The patient has chronic pain Patients with neurological or mental disorders Long-term use of sedation, painkillers and antipsychotic drugs The patient has contraindications for opioid use