Differential diagnosis of high erythrocyte distribution width: 1. High erythrocyte pressure product: The erythrocyte pressure product helps to understand the increase and decrease of erythrocytes, and when the absolute value of erythrocytes increases due to various causes, there is a corresponding increase in erythrocyte pressure product. High erythrocyte pressure product is found in the patient’s blood tests after shock. 2, erythrocytosis – hyperviscosity: erythrocytosis – hyperviscosity syndrome is a relatively common disease in the neonatal period, due to erythrocytosis, blood stagnation, slow blood flow, prone to poor tissue perfusion and hypoxia and damage to the heart, brain, kidneys and other multiple organs, part can affect the long-term prognosis of the nervous system. 3, erythrocytosis: erythrocytosis is the number of red blood cells per unit volume of blood is higher than the normal value of the high limit. It is generally believed that the erythrocytes are increased when the erythrocytes are >6 million/mm3 in adult males and >5.5 million/mm3 in adult females after several examinations. Relative increase is seen in hemoconcentration; absolute increase is seen in plateau life, fetus and newborn, strenuous physical labor, serious cardiopulmonary disorders and true erythrocytosis. Prevention: Strengthen education on nutrition, correct partial eating habits and incorrect cooking habits. Infants should advocate breastfeeding and reasonable feeding. In areas with a high prevalence of nutritional megaloblastic anemia, recipes should be actively promoted for improvement. Folic acid prophylaxis should be given to those with chronic hemolytic anemia or long-term antiepileptic drugs, and total gastrectomy patients should be given prophylactic intramuscular injection of vitamin B12 once a month. Strengthen education on nutrition and correct partial eating and poor cooking habits. Do not abuse alcohol. Patients on hemodialysis and gastrointestinal surgery should strengthen nutrition and supplement folic acid and vitamin B12. folic acid and vitamin B12 should be supplemented in time when taking drugs that affect the absorption and utilization of folic acid and vitamin B12. infants should advocate breastfeeding, reasonable feeding and timely addition of complementary foods. Pregnant women should eat more fresh vegetables and animal protein, and supplement folic acid in the second trimester.