Abstract: Notch signaling can control T cell development and differentiation and lead to acute T cell lymphoma/leukemia (T-ALL). Most Notch1mutations in human T-ALL are the HD domain and the PEST domain. Aberrant Notch1activation can induce T-ALL by PI3K/Akt, mTOR or/and NF-κB pathways. Some recent reports suggested that Notch signaling could not only control T cell development,but also has a role in acute myeloid leukemia (AML) and Graft-versus-host Disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Moreover,Notch signaling can regulate the expansion of HSC as well as generate increased numbers of progenitor cells which are capable of rapid repopulation to improve HSC homeostasis and hematopoietic recovery after allo-HSCT.