Gastrointestinal mesenchymal tumors (GIST) are a group of tumors that originate independently from the primitive mesenchymal tissue of the gastrointestinal tract and are a type of gastrointestinal tumor with malignant potential. It can occur in any part of the GI tract. The most common sites of predilection are the stomach (60%-70%) and the small intestine (20%-30%). Pathogenesis: It is mainly caused by functionally acquired mutations in the C-Kit (85%) and platelet-derived growth factor receptor alpha (PDGFRA, 7%) genes. Main clinical manifestations: The most common first symptom is gastrointestinal bleeding. Patients usually come to the hospital with symptoms of anemia, such as dizziness, weakness or black stool, and also abdominal discomfort, abdominal mass, abdominal pain, etc. There are also many patients without obvious clinical manifestations. The main diagnostic tools: 1, ordinary white light endoscopy 2, ultrasound endoscopy, can be clearly diagnosed by lesion echo as well as fine needle aspiration biopsy 3, CT risk classification: malignant GIST has a poor prognosis, with a recurrence rate of up to 50% at 5 years after radical resection and a previous median survival of only 9 months for metastatic GIST. Therefore, it is necessary to grade the risk of GIST, which is related to lesion size, site, mitotic count, surgical margins, and tumor rupture, among which lesion size, site, and mitotic count are the most important grading parameters. How to treat: Clinical workers should strictly assess the GIST risk classification and give the best treatment measures. In general, for upper GIST with diameter ≤2 cm, EUS follow-up is recommended; for GIST with diameter >2 cm, radical surgical resection is preferred, and minimally invasive treatment is feasible for those with indications for laparoscopic or endoscopic treatment; for rectal GIST of any size, radical surgical resection is preferred; for lesions not suitable for surgical resection, postoperative residual foci (R1 surgery), tumor rupture, and recurrent and metastatic foci, all are currently Imatinib adjuvant chemotherapy or neoadjuvant chemotherapy is recommended. Patients with GIST who respond reasonably well to conventional doses of imatinib should have their CT reviewed every 3 months to assess the efficacy.