Leukemia is the most common malignant disease in children, and with the one-child policy in China, children have become the focus of life for several generations in the family. Combination chemotherapy for high-risk childhood leukemia has failed to achieve satisfactory outcomes, and long-term chemotherapy survival rates and quality of survival are low, causing serious economic and psychological burdens to families and society. However, the lack of donors makes allogeneic transplantation extremely limited, and it is extremely difficult to find matched donors for pediatric leukemia patients in China. HLA hemizygous-related transplantation and transplantation between HLA-identical siblings have basically solved the donor problem, but the literature is mostly limited to adults because of the high incidence of graft implantation failure, severe GVHD and slow reconstruction of immune function, and pediatric leukemia Poor compliance and tolerance to such transplantation is more difficult to perform, and related reports are rare. Multifactorial analysis has shown that long-term disease-free survival of children is significantly associated with disease status at the time of transplantation and the degree of acute graft-versus-host disease. It has been observed [8] that the incidence of grade III-IV acute GVHD after allogeneic stem cell transplantation in children under 10 years of age in first complete remission is low, with a disease-free survival rate of 67% at 6 years. 32% and 21%, respectively. Children with leukemia are more likely to receive high-dose CD34+ cell infusions than adults, and observations have shown [10] that high-dose CD34+ 8. ×0106/kg (1.3-18.0) infusion accelerates donor stem cell implantation, faster hematopoietic recovery, and aGVHD incidence of 26% in the 17 hemiphasic groups, with no incidence of aGVHD above II, to some extent reducing the incidence of GVHD. The incidence of GVHD was reduced to some extent. In addition, it is crucial to use different immunosuppressant combinations at different transplantation stages to control the occurrence of induced host disease against graft and graft against host disease bi-directional immune rejection at an early stage [11] . The classical pretreatment regimen for HSCT is cyclophosphamide plus systemic radiotherapy or high-dose marilyn plus cyclophosphamide, and we used systemic radiotherapy + cytarabine + cyclophosphamide for pretreatment, and all children who received systemic radiotherapy have survived to date. There was no significant decline in mental diet from normal throughout the transplantation in children with leukemia, and none had severe oral mucositis. Biochemical examinations showed no significant impairment in the function of important organs, no hemorrhagic cystitis, early implantation of hematopoietic function, and low transfusion of blood products during transplantation. The recovery of immune function after transplantation was relatively fast in this group of children, with NK cells returning to normal 3 months after transplantation and the absolute number of CD4+ cells reaching 200/ul within 6 months after transplantation, resulting in a decrease in the incidence of serious infections. The incidence of infection is prevented to some extent. It should be emphasized that careful medical and nursing care in children with leukemia hemimelanotic bone marrow transplantation is the basis for successful transplantation, and it is extremely important to carefully observe changes in the child’s condition, detect problems early, make a clear diagnosis early, and treat them decisively. Our results show that after 8 consecutive haploidentical bone marrow transplants, only 1 case of acute GVHD above II occurred, with 0% transplant-related mortality at 180 days and a median follow-up of 33 months, and 6 cases survived without disease, which is an encouraging result. However, the small number of cases can only provide a little experience for this type of leukemia transplantation. The current long-term prognosis of AML in children is inferior to that of acute lymphatic leukemia, with a high incidence of drug resistance and infection during treatment, long-term chemotherapy causing damage to organ functions and affecting long-term quality of life, and a 5-year disease-free survival rate of only about 40%. The improved survival was mainly related to the significantly lower relapse rate in the auto-BMT and chemotherapy groups. Therefore, in childhood AML, except for a few types such as AML-M3, once complete remission is achieved, HSCT should be performed as early as possible if conditions allow. Our experience suggests that haploidentical undescended T-cell bone marrow transplantation for childhood leukemia is safe, feasible and effective for clinical use.