Gastroscopy is the most important examination method for gastric cancer. Gastroscopy can observe the condition of patient’s stomach and take out part of stomach tissues to diagnose whether there are lesions; 2. Local CT or MRI: It can determine the location of tumor, chest CT can diagnose whether gastric cancer involves esophagus and whether there are lung metastases, pelvic CT or MRI can diagnose whether gastric cancer has metastasized to ovaries, and head CT or MRI can observe whether there are brain metastases.