The causes of anemia in children include insufficient production of red blood cells or hemoglobin, hemolytic anemia, and hemorrhagic anemia. 1. Insufficient production of red blood cells and hemoglobin: ① raw material deficiency: including iron deficiency, vitamin B₁₂ and folic acid deficiency, vitamin A, vitamin B₆ deficiency, and protein deficiency. ② Hematopoietic disorders: aplastic anemia. ③ Infectious and inflammatory anemia, such as Haemophilus influenzae infection. 2. Hemolytic anemia: Hemolysis caused by intrinsic abnormalities of red blood cells, such as structural defects of red blood cell membranes, erythrocyte enzyme deficiencies, and so on. Erythrocyte extrinsic factors, such as hemolytic disease of the newborn, infections, toxins, hypersplenism, etc. 3. Blood loss anemia mainly includes acute blood loss anemia and chronic blood loss anemia. Children’s anemia may also be other causes, the patient should go to the hospital as soon as possible to improve the examination, to clarify the cause of the disease and follow the doctor’s instructions for treatment.