Endoscopy combined with tissue biopsy can lead to a definitive diagnosis of many gastrointestinal diseases (mainly superficial mucosal lesions), but endoscopy is often unable to make a diagnosis of lesions deeper in the mucosa and below, and elevated gastrointestinal tract lesions compressed by extra-gastrointestinal organs or lesions. Endoscopic Ultrasonography (EUS): An ultrasound probe is introduced through the endoscope, and the wall of the digestive tract or neighboring organs are tomographed under direct endoscopic visualization through the body cavity, and ultrasound images of the submucosal layers of the digestive tract wall and the surrounding neighboring organs are obtained. It can directly scan the suspected lesion and its surroundings under direct endoscopic visualization, thus obtaining clear ultrasound images and accurately displaying the level of the lesion in the wall of the digestive tract or its relationship with the wall of the digestive tract.EUS can suggest the nature of the lesion according to its level of origin, and the strength of the echo of the lesion, homogeneity, margins, and the nature of the surrounding lymph nodes, and it is the best method of diagnosis of submucosal lesions of the digestive tract at present. It is the best method to diagnose submucosal lesions in the digestive tract. The diagnosis of submucosal lesions by ultrasound endoscopy can be used to further guide the treatment such as minimally invasive endoscopic treatment or surgical treatment and postoperative follow-up according to the diagnostic results of endoscopy. EUS diagnosis can help to strictly control the indications for various treatments, which can lead to good efficacy and effective postoperative follow-up. Applying EUS examination for preoperative evaluation can effectively estimate possible intraoperative and postoperative situations and preventive measures, and fully communicate with patients and their families. EUS is relatively simple and safe, and the postoperative follow-up examination of patients has no adverse reactions. It provides a new and effective way to guide the development of diagnosis and treatment plan and postoperative follow-up for patients with submucosal occupations in the gastrointestinal tract.