It is not necessarily true that there is a high risk of rejection and a low risk of relapse after a leukemia transplant. This is analyzed on a patient-by-patient basis. The size of rejection after leukemia transplantation is related to the match between the provider and the supplier, the medication, and the patient’s physical condition. 1. Rejection after leukemia transplantation: rejection is a reaction of the donor’s lymphocytes to recognize the other and attack the other’s cells, and the different surface antigens will be attacked by the autologous lymphocytes. Generally twins have fewer surface antigen differences, so the degree of rejection is lower than in hemizygosity. If the medication used in the rejection is effective it can also reduce the rejection reaction. The patient’s good physical condition can reduce the complication, also can reduce the rejection reaction. 2. Recurrence rate of leukemia transplantation: the reason of recurrence after leukemia transplantation is mainly related to the incomplete elimination of leukemia cells at the time of transplantation. If the leukemia cells are not completely removed at the time of transplantation, the relapse rate is still very high. Therefore, the size of rejection and relapse after leukemia transplantation is related to many factors and should be treated differently. The same leukemia transplant patients have different results due to different physical conditions, different genetic matches and different treatment methods. Standardized treatment should be carried out under the guidance of doctors.