Severe aplastic anemia is a type of aplastic anemia with rapid onset and severe disease. The main clinical manifestations include progressive worsening of anemia, dizziness, weakness, pallor, panic, shortness of breath, and difficulty in breathing. Most patients develop high fever in the early stage of the disease, and common infection sites include respiratory system infection, digestive system infection and urinary system infection, which are usually difficult to control, and mostly combined with sepsis, patients also have skin and mucous membrane bleeding and organ bleeding. For the treatment of severe aplastic anemia, anti-lymphocyte globulin or anti-thymocyte globulin is preferred, which can be combined with cyclosporine for intensive immunosuppressive therapy. For patients with granulocyte deficiency, leukocyte-raising therapy with granulocyte colony-stimulating factor is also indicated. For patients older than 40 years of age with severe reoccurrence and a suitable donor, early allogeneic hematopoietic stem cell transplantation is recommended as a possible cure for the disease.