The last blind spot: The 6-meter-long small intestine is the last blind spot of the digestive system. Although modern advanced endoscopic techniques can accurately diagnose and treat upper and lower gastrointestinal disorders, the small intestine is far from the mouth and anus, especially because of its curved and free characteristics, which makes it difficult to insert the whole small intestine for its efficacy. Various traditional examination methods are also unable to meet the clinical diagnostic requirements due to their low sensitivity and accuracy. Therefore, the positive rate of diagnosis of the whole small intestine is not satisfactory. Introduction of capsule endoscopy: In 2001, capsule endoscopy was introduced. It is an attractive and painless method for small bowel examination. However, the current capsule endoscopy cannot be localized and oriented in the body, cannot be biopsied, cannot be treated, cannot be guaranteed to be expelled from the body and the images are not clear enough to be of definite clinical value. Moreover, capsule endoscopy is single-use and the cost of examination is too high. Double-balloon whole small intestine electronic endoscopy: It has overcome the last blind spot in the gastrointestinal tract, and can reach the middle and lower ileum under normal circumstances, and part of it can reach the terminal ileum, so the scope of examination is obviously extended, and it has a wide field of view, clear image quality and basic functions such as inflation, suction and biopsy, which is a powerful weapon for diagnosis and treatment of small intestine diseases. Indications: Gastrointestinal bleeding of unknown origin. Crohn’s disease (Crohn’s disease) with abnormal small bowel imaging. Chronic abdominal pain, chronic diarrhea, suspected organic lesions of the small intestine. Multiple polyp syndrome. Small bowel cancer.