Allogeneic hematopoietic stem cell transplantation(allo-HSCT) is an effective therapy to cure hematological malignancies. However, recipient's risk of developing hepatitis B after transplantation is increasing due to receiving graft infected with hepatitis B virus (HBV) and seriously impaired immune function. Entecavir and tenofovir are currently recognized as effective drugs for the prevention and treatment of hepatitis B in recipient, significantly reducing liver damage after transplantation. The immune reconstitution of recipient takes a long time and has hete-rogeneity, so the best duration of post-operative monitoring and antiviral prophylaxis is not clear. This article reviews the mechanism of hepatitis B virus reactivation, the characteristics of hepatitis B and the recent advance in prevention and treatment of hepatitis B after allo-HSCT.