The cause of leukemia M3 is not completely clear, there may be biological factors, physical factors, chemical factors, genetic factors and other blood diseases. 1. Biological factors: mainly viral infection and abnormal immune function, after viral infection of the organism, as endogenous virus latent in the host cells, once activated expression, thus inducing M3 leukemia. 2. Physical factors: including X-rays, gamma rays and other ionizing radiation. Studies have shown that extensive and high-dose irradiation can lead to bone marrow suppression and decreased immunity, DNA mutation, breakage and recombination, thus leading to the development of M3 leukemia. 3. Chemical factors: years of exposure to benzene and organic solvents containing benzene are related to the occurrence of M3 leukemia, ethylenediamine has strong chromosomal aberration-causing and leukemia-causing effects, and alkylating agents in antitumor drugs have leukemia-causing effects. 4. Genetic factors: familial leukemia accounts for about 0.7% of leukemia, monozygotic twins, if a person occurs leukemia, the other person’s incidence rate is 20%. 5. Other blood diseases: such as lymphoma, multiple myeloma and so on. These diseases, in the late stage, can widely invade various organs such as liver, spleen, lymph nodes, bone marrow, etc. Abnormal early granulocyte differentiation in bone marrow is blocked, malignant clones and inhibit normal hematopoiesis, which may eventually develop into M3 type leukemia. In conclusion, the cause of M3 leukemia is not completely clear, once diagnosed, it is necessary to go to the hematology department and receive regular treatment under the guidance of physicians. Currently, the cure rate of M3 leukemia is the highest among all acute leukemias.