Leukemia is a malignant disease of the hematopoietic system, a malignant lesion of hematopoietic stem cells caused by a variety of factors. The following factors tend to lead to the development of leukemia: 1. Chemical factors: the most common in the country, including pollution, toxic contamination, chemical poisons, etc. For example, gums, which contain benzene and benzene derivatives. In addition, including decorative pollution of toxic substances formaldehyde can lead to leukemia, as well as the use of herbicides, pesticides and other chemical toxic substances in rural areas, is the most common cause of leukemia in China; 2, physical factors: physical factors usually the people are exposed to less, like radiation, X-rays, in addition to nuclear contamination after the atomic bomb explosion in Hiroshima, Japan, or nuclear pollution caused by nuclear leaks like the Fukushima nuclear power plant, then This radiation can also cause leukemia; 3, biological factors: biological factors directly caused by leukemia virus in Japan has been found, in China has not been found; 4, hereditary factors: genetic susceptibility, that is, some members of the family suffer from leukemia, other members of the immediate blood relatives when they are also prone to leukemia, this is the genetic factors.