The HSCT process is divided into the following parts: 1) donor search, donor search is mainly to do HLA matching, to find a fully compatible donor, or now a semi-compatible donor can also be chosen, this is the first part; 2) if the corresponding donor is found, the patient enters the transplantation ward to do the transplantation process, to do the transplantation start this part is called pretreatment, pretreatment is to clear the patient’s own bone marrow to make room for the donor’s cells; 3) transfusion of donor HSCT. This part is called pre-treatment, which is to clear away the patient’s own bone marrow to make room for the donor’s cells; 3, transfusion of the donor’s hematopoietic stem cells. The sources of hematopoietic stem cells are generally divided into bone marrow stem cells, peripheral blood stem cells, and umbilical cord blood stem cells. Such as the usual blood transfusion from the vein infusion of hematopoietic stem cells; 4, hematopoietic reconstruction and immune reconstruction.