Malnutrition is common in the diagnosis and treatment of patients with hematological tumor. Chemotherapy, as the most important treatment of hematological tumor, aggravates the malnutrition of patients further. The main reason is the nausea, vomiting and reduced food intake caused by chemotherapy. The significant increase of C⁃reactive protein after induction treatment indicates that the incidence of infection and the level of inflammation are high, which may interfere with the body's metabolism and aggravate the deterioration of nutritional status to a certain extent. Malnutrition in patients with hematological tumor is characterized by abnormal body mass index, abnormal body composition, abnormal overall/comprehensive evaluation and abnormal biochemical indexes. The principle of nutritional treatment for patients with hematological tumor is similar to that of other tumor, with enteral nutrition as the main and parenteral nutrition as the supplement. However, special nutrients should be supplemented: ①glutamine; ②diet for "granulocytopenia"; ③ω⁃3 polyunsaturated fatty acids; ④ bovine colostrum and soybean diet. Through nutritional screening and evaluation, formulating nutritional treatment plans for patients with hematological tumor at different treatment stages and timely and appropriate individualized nutritional treatment can significantly improve the nutritional status of patients with hematological tumor, prevent malnutrition and