Thalassemia is a hereditary disease that causes hemolytic anemia due to impaired synthesis of peptide chains. Thalassemia is classified into mild thalassemia, moderate thalassemia and severe thalassemia according to the severity of the disease. The routine blood characteristics of these three types of thalassemia are: i. For mild thalassemia, hemoglobin is normal; for moderate and severe thalassemia, hemoglobin is below normal. Whether it is mild thalassemia, moderate thalassemia, or severe thalassemia, their average red blood cell volume is reduced, and the more severe the anemia, the smaller the average red blood cell volume. Second, the average red blood cell hemoglobin volume is reduced in either thalassemia, and the more severe the anemia, the lower the average hemoglobin volume. Third, the average hemoglobin concentration is generally normal in thalassemia patients, and there is no significant difference.