Reduced platelet after one month of leukemia transplantation is considered to be related to infection, unrecovered hematopoietic function of bone marrow transplantation, use of chemotherapeutic drugs, etc., and can be treated by anti-infection, promoting bone marrow hematopoietic drugs, platelet transfusion and other treatments. 1. Infection: after bone marrow transplantation for leukemia, if viral or bacterial infection occurs, it can cause platelet decrease, at this time, it can be treated by anti-infection, such as levofloxacin, and generally can be restored to normal. 2. Bone marrow transplantation hematopoietic function has not been restored: after bone marrow transplantation, if the transplant recipient due to autoimmune factors can lead to bone marrow hematopoietic function has not been fully restored, can be through the promotion of myelopoietic drug therapy. For example, granulocyte colony-stimulating factor and thrombopoietin. 3. Use of chemotherapeutic drugs: after successful bone marrow transplantation, chemotherapy may be continued in order to consolidate the treatment. Chemotherapeutic drugs can also cause platelet reduction, which can be recovered after the end of chemotherapy. In addition, if the platelet decrease is very serious, in order to avoid the occurrence of bleeding, it can also be supported by platelet transfusion. Reduced platelets after leukemia transplantation may also be related to other causes, which should be identified under the guidance of the doctor and standardized treatment, so as to avoid delaying the condition. In addition, the above drugs should also be used under the guidance of a doctor.