Fever and vomiting blood in children can be seen in many kinds of diseases, mainly the following: first of all, the most common is due to severe respiratory infections, dryness and lack of water in the body, fire or do not drink water, will lead to fever symptoms of vomiting blood; secondly, see in the blood system diseases, such as acute leukemia patients, due to a decrease in the number of white blood cells, or a decrease in the number of platelets, etc., the hematopoietic function is destroyed; then see in the digestive system diseases, if the stomach mucosa erosion, bleeding for various reasons, will also have fever, vomiting blood symptoms. Then, if the stomach mucosa is eroded and bleeding due to various reasons, fever and vomiting of blood will also occur. Therefore, the diagnosis should be made based on the specific medical history, symptoms and signs, and auxiliary examinations. Fever is mostly caused by bacterial or viral infections, and the pathogens should be actively identified and treated accordingly.