Newborn screening for diseases includes the following: thyroid function, 21-hydroxy conditions, serotonin, thalassemia, and phenylketonuria. Because these problems have a large impact on the baby and can be avoided by early treatment, newborns are screened as long as they are born in a regular hospital. If the baby was born in another hospital and no such screening was done, it is recommended that the baby be screened for newborn diseases in a regular hospital, and the sooner the better. The prerequisite is that the baby should be satisfied with the opening of the breast, after about 2-3 days, before considering this test. Through early detection and early treatment, more problems can be avoided, such as hypothyroidism, we can control these conditions through medication; for example, the baby’s sericea, early detection has a greater guidance significance for the subsequent jaundice or to avoid his hemolysis; for example, the early occurrence of phenylketonuria can be prevented and controlled through special food. If there is a problem with 21-hydroxy, it indicates a problem with endocrine metabolism, which can affect the growth and development of the child, so early detection can be handled by medication.