Gastrointestinal mesenchymal tumor is a disease that was often misdiagnosed and underdiagnosed in the past, and has only been properly recognized and received increasing attention in the last decade. As a relatively rare type of tumor, the incidence of gastrointestinal mesenchymal tumor in Shanghai is about 23 per 1 million, accounting for 1% to 4% of gastrointestinal tumors. The general age of onset is 55 to 60 years old. 60% to 70% of gastrointestinal mesenchymal tumors occur in the stomach, 20% to 30% in the small intestine, and a small percentage in the esophagus, colon or rectum. Gastrointestinal mesenchymal tumors are not the same as stomach or intestinal cancer. Cancer is a malignant tumor that occurs in the epithelium and is characterized by infiltrative growth and easy recurrence and metastasis. Gastrointestinal mesenchymal tumors, on the other hand, occur in the mesenchymal tissues of the gastrointestinal tract and are not as locally invasive as cancer, metastasizing less through the lymph nodes and more through the bloodstream. This means that this tumor has three main characteristics: 1. It is not sensitive to conventional radiotherapy and chemotherapy, and surgical resection is its main treatment of choice, and molecular targeted drugs can also be used as adjuvant therapy. 2. It is prone to recurrence after surgery. Although gastrointestinal mesenchymal tumors of low risk level have a high 5-year survival rate after complete resection, with the increase of risk level, the postoperative recurrence and metastasis rate is as high as 40% to 90%, and once the recurrence and metastasis, the survival time is only 10 to 20 months, and the majority of patients recur within two years after the first resection, and some even recur after 10 years. 3. Early diagnosis is not easy. Due to the lack of obvious symptoms and specificity, gastrointestinal mesenchymal tumors are often difficult to be detected early, especially for tumors less than two centimeters in diameter, which may not have any symptoms. The common early manifestations of most patients are mainly gastrointestinal bleeding, abdominal pain, abdominal mass and anemia. Some patients may show symptoms of intestinal obstruction. Many patients are inadvertently found to have this disease during tumor screening, physical examination or other surgeries. Imaging examination is important for the diagnosis of gastrointestinal mesenchymal tumor, and the current diagnosis mainly relies on fiberoptic endoscopy, endoscopic ultrasound, B ultrasound and CT. In particular, we remind that once symptoms such as gastrointestinal bleeding, including vomiting blood, blood in stool or black stool, as well as abdominal masses found, frequent unexplained abdominal pain or anemia that is difficult to be explained by other causes, you should promptly visit a regular hospital and undergo ultrasound endoscopy if necessary. If no lesion is found during gastroscopy, it is better to perform small intestinal microscopy again to avoid missing the diagnosis.