The normal rate method for lactate dehydrogenase in children should be 120~250U/L, 300U/L exceeds the normal value, the cause needs to be identified in time, which is more serious. Lactate dehydrogenase exists in all tissues of the body, the normal rate of lactate dehydrogenase in children should be 120~250U/L, 300U/L over the normal value, more serious. When lactate dehydrogenase is elevated, it often suggests certain diseases such as myocardial infarction, liver diseases such as acute viral hepatitis, cirrhosis, stagnant jaundice, etc., certain malignant tumors, or anemia, pulmonary infarction, skeletal muscle injury, shock, renal disease and so on. Therefore, when children are found to have elevated lactate dehydrogenase, they should consult a doctor in time and under the guidance of the doctor, pay attention to daily rest, avoid exertion, pay attention to a balanced diet and eat more nutrients.