It is currently considered to be a hematopoietic dysfunction due to abnormal proliferation and differentiation of hematopoietic stem cells. The main manifestations are a decrease in peripheral blood whole blood cells and bone marrow cells that proliferate but have abnormal morphology and fail to mature (pathological hematopoiesis). Some patients transform into acute leukemia after a certain period of myelodysplastic syndrome; some die due to infection, bleeding or other causes and never transform into acute leukemia during the course of the disease. It is classified as primary and secondary (after long-term chemotherapy or radiotherapy, or secondary to tumors, autoimmune diseases, etc.). According to the characteristics of hematology and bone marrow morphology, in 2008 WHO classified MDS into 7 types: refractory hematocrit with unilineage morphologic abnormalities (RCUD), refractory anemia with ring iron granulocytes (RARS), refractory hematocrit with multilineage morphologic abnormalities (RCMD), refractory anemia with primitive cytosis – type I (RAEB-1), refractory anemia with primitive The disease has an insidious onset and is more common in middle-aged and older men, with about 70% of cases over 50 years of age. It is rare in children, but in recent years the incidence in adolescents has also increased. The clinical manifestations are diverse, lacking specific manifestations, and often presented with anemia, bleeding and infection. Some patients may have mild enlargement of the liver, spleen, and lymph nodes, which may occur simultaneously or separately, and are easily overlooked because of their insignificant degree. A small number of patients may have sternal pressure pain, rib or limb joint pain. Prevention: Although the causes of myelodysplastic syndromes are unclear, many are due to clonal cell proliferation abnormalities caused by biological, chemical or physical factors. Therefore, drugs should be used with caution, radiation therapy should also be strictly grasped for indications, and labor protection should be done when exposed to harmful substances such as chemicals (e.g. benzene, polyvinyl chloride) in relevant industrial and agricultural production. Treatment: supportive therapy, immunosuppressive therapy, immunomodulatory therapy, differentiation inducers, epigenetic modification therapy, cytotoxic chemotherapy, hematopoietic stem cell transplantation and traditional Chinese medicine. Prognosis: MDS is a heterogeneous disease with a wide variation in survival between types. Infection, bleeding and conversion to AML are the main causes of death.