Leukemia is a malignant disease of the hematopoietic tissue, also known as "blood cancer". Its characteristics are that a large number of leukemic cells proliferate without limit in the bone marrow and other hematopoietic tissues, and then enter the peripheral blood, while the normal production of blood cells is significantly inhibited. This article focuses on the daily prevention of leukemia, early detection, early treatment, postoperative care and rehabilitation, with an emphasis on childhood leukemia.