Moderate anemia means that the concentration of hemoglobin in peripheral blood is between 60-90 g/L. There are many causes of moderate anemia, the common ones are: i. Iron deficiency anemia can appear as moderate anemia due to insufficient intake of iron or impaired absorption of iron, as well as having chronic blood loss, which can cause moderate iron deficiency anemia over time. Second, megaloblastic anemia, due to the lack of folic acid and vitamin B12, the body cannot synthesize mature red blood cells normally, and moderate megaloblastic anemia can also occur. Aplastic anemia, which is a bone marrow hematopoietic failure disease, also occurs as moderate anemia due to damaged hematopoietic stem cells that cannot synthesize red blood cells normally. Fourth, patients with acute leukemia also develop moderate anemia due to the destruction of hematopoietic function.