The causes of aplastic anemia in children are not yet clear, and it is generally believed to be related to four factors: 1. viral infection, such as hepatitis virus, after children have been infected with hepatitis virus, the chance of aplastic anemia is greater; 2. chemical factors, such as children taking oral sulfonamide drugs, cytotoxic drugs, chloramphenicol, etc., will lead to the occurrence of reblast; 3. physical factors, long-term exposure to X-rays will lead to children’s reoccurrence; 4. Related to children’s susceptibility and genetic factors, it is currently believed that children’s reoccurrence is under the influence of susceptibility factors and genetic factors, which can lead to abnormal immune response of bone marrow and the tendency of disorder of fragile hematopoietic cell proliferation. The traditional doctrine is that aplastic anemia is the occurrence of abnormal hematopoiesis in the bone marrow hematopoietic tissue against the background of certain genetic factors.