At present, there are more means to confirm the diagnosis of gastric cancer in clinical practice, including blood test, barium meal examination of upper gastrointestinal tract and gastroscopy, among which the most accurate, reliable and direct diagnostic method is gastroscopy. Gastroscopy is a magnified soft mirror that enters the stomach through a soft mirror of 1cm in diameter and 1-1.5m in length to visually detect the inflammation of lesions in the stomach, while special staining of suspicious lesions, magnified endoscopy and BNI examination are done to more finely assess the lesions in the stomach. If necessary, biopsy can be performed at the suspicious location in the stomach for pathological examination, which provides very strong evidence for the final diagnosis of gastric cancer. Therefore, once gastric cancer is suspected or there is a family history, patients are advised to screen for gastric cancer, and the most reliable and accurate method is gastroscopy.