Patients with refractory and relapsed leukemia have very poor outcomes and low survival rates with combination chemotherapy, and allogeneic HSCT is the only possible way to obtain a cure for relapsed leukemia. However, even with conventional transplantation techniques abroad, the outcome of patients with refractory and relapsed leukemia is still poor, mostly with advanced leukemia, with survival rates of only 20-30%, and the main reason for failure is the high rate of post-transplant relapse and higher transplant-related comorbidities. The technical complexity of transplantation for refractory relapsed leukemia, in recent years we have made great progress in technological innovation and have accumulated extensive experience in the selection of transplantation timing and application of immunotherapy, haplotype transplantation selection of KIR incompatible donors and replacement of “peripheral blood stem cell infusion by G-CSF mobilization” with “We have experience in haploidentical secondary complex transplantation, and haploidentical transplantation has stronger anti-leukemic effect, and many relapsed leukemia patients have achieved good results after haploidentical secondary transplantation, improving the poor prognosis of patients. This has opened the way for relapsed leukemia patients to regain their lives. The results are encouraging as studies have shown survival of more than 50% after transplantation in relapsed and refractory leukemia.