Abstract: Acute leukemia (AL) is a malignant clonal disease caused by hematopoietic stem cells. Depending on the cell type involved, AL is classified as acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML). Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important and effective treatment for patients with AL to achieve long-term survival. However, recurrence after transplantation remains the primary cause of death. Pretransplantation status, transplantation conditioning, and prevention of post-transplantation relapse affects post-transplantation outcomes. This review focuses on post-transplantation maintenance therapy. Several studies on post-transplantation maintenance therapy are discussed, including research on post-transplantation maintenance therapy with epigenetic drugs, targeted drugs, and immunologic drugs.