The common diseases in hematology include iron deficiency anemia, aplastic anemia, leukemia, lymphoma, myeloma, and immune thrombocytopenic purpura. Iron deficiency anemia is mostly seen in women of childbearing age and children, and is caused by iron deficiency in the body due to picky eating or heavy menstruation, etc. Clinical treatment with oral iron supplementation is very effective. Aplastic anemia is due to autoimmune dysfunction and enhanced T-cell function, resulting in the failure of hematopoietic stem cells. Patients show trilineage reduction and can have symptoms such as anemia, infection and bleeding. Leukemia is a malignant clonal disease of hematopoietic stem cells. Patients can have symptoms such as infection, bleeding, anemia, and also clinical manifestations of infiltration of organs. Lymphoma is a malignant tumor of lymphatic tissue. Patients may have fever and enlarged lymph nodes. Multiple myeloma is due to malignant transformation of plasma cells, and patients may have symptoms such as bone destruction, kidney damage and anemia and infection. Immune thrombocytopenic purpura is due to the production of autoantibodies against platelets, which causes destruction of platelets and a decrease in platelet count, resulting in extensive skin and mucosal bleeding.