Patients have been inquiring about the knowledge of ultra-fine gastroscopy, which is summarized as follows: Ultra-fine gastroscopy has the following advantages over ordinary gastroscopy: 1. Fine: the mirror body is fine. The diameter of a normal gastroscope is 10 mm. The diameter of the transnasal ultra-fine gastroscope is only 5.9 mm. 2. Soft: The mirror is soft. Ultra-fine gastroscope is far softer than ordinary gastroscope, like a thick noodle, patient pain is not obvious. 3, true: the image is clear and realistic. Ultra-fine gastroscope use the latest digital imaging technology, super CCD, the image is clearer and more realistic. 4, less: less pain, less danger, less complications. For children, acute and critical illnesses, old and frail patients and patients with poor cardiopulmonary function, ultra-fine gastroscopy has more advantages. 5, high: higher diagnostic accuracy, better effect of certain treatment under the mirror, and higher safety factor. 6, more: First, more insertion routes. Ultra-fine gastroscope can be inserted from the nasal cavity, but also from the oral cavity, and does not require special treatment. Secondly, it has many roles. Transnasal ultra-fine gastroscope can be used for esophageal disease examination, gastric disease examination, H. pylori examination, pathological biopsy and microscopic intervention, and can also be used for gastric cancer screening. The normal gastroscope is not suitable for gastric cancer screening because it is too thick and painful for patients during examination. Japanese scholars have used transnasal ultra-fine gastroscopy for physical examination to detect early gastric cancer. Capsule endoscopy cannot replace routine examination of the upper gastrointestinal tract because it cannot be biopsied, has a limited field of view, and is expensive. In addition, the patient can talk directly with the doctor during the transnasal gastroscopy, which can eliminate the patient’s tension and anxiety and make the examination process completed in a relaxed and pleasant environment. However, transnasal ultra-fine gastroscopy is not suitable for patients with nasal stenosis, significant curvature of the nasal septum, acute rhinitis, etc. Although it has considerable advantages in some gastroscopic treatments such as upper gastrointestinal stent placement and jejunal nutrition tube placement, it is not suitable for the treatment of gastric polyps or gastric bleeding.