Intestinal vascular malformations, including arteriovenous malformations, vascular dilatation, hemangioma, vascular dysplasia, etc., are one of the causes of acute or chronic lower gastrointestinal bleeding, which is often an abnormality of the blood vessels themselves, or one of the manifestations of a certain systemic disease or a syndrome. Clinical examination methods are mainly based on the following points. Repeated intermittent bleeding and chronic small amount of bleeding, the total number of red blood cells and hemoglobin content in the blood are decreased; fecal occult blood test is positive. 1.Selective intestinal angiography selective or highly selective angiography is the main means of diagnosing this disease: vascular malformations in angiography can be divided into 3 types: type I for arterio-venous anastomosis or submucosal vascular dysplasia; type II for vascular malformations; type III for hemorrhagic capillarisations. The main signs after angiography are: ① abnormally increased vascular plexus with structural disorder. ② Spider-like dilatation and tortuosity of peripheral blood vessels. (iii) Early visualization of veins in the arterial phase, showing the “double-track” sign, suggesting that there is a shunt between the artery and vein. In the hemorrhage stage, the contrast agent can be seen to spill out and accumulate in the intestinal lumen. In the venous phase, the veins in the intestinal wall on the side of the mesenteric border are dilated and tortuous. 2.Endoscopic examination: electronic gastroscopy, small bowel microscopy, colonoscopy and other endoscopic examinations have become the first choice of diagnosis of vascular malformations, and in recent years, capsule endoscopy has been carried out on the diagnosis of small intestinal vascular malformations, the positive rate of which can reach more than 90%.