Down’s syndrome, also known as trisomy 21, is the most common chromosomal aberration caused by congenital mental retardation, growth retardation, with special facial features (small eye fissures, wide eye spacing, upward sloping external canthus of both eyes, flattened nasal bridge, small external ears, etc.), multiple malformations of the internal organs of the limbs and changes in skin texture. Based on their specific facial features, skin texture characteristics and low intelligence, clinical diagnosis can be made in typical cases, while karyotype analysis is required for children with atypical symptoms or chimeric low intelligence. Typical features of neonates with Down’s syndrome are: drowsiness, hoarse crying, feeding difficulties, abdominal distention, constipation, diminished embrace reflex, hyperflexion of joints, skin drop at the back of the neck, facial flattening, upward sloping lid fissures, auricular malformations, pelvic hypoplasia, hypoplasia of the middle finger of the fifth finger, broken palm, possible mental retardation, hearing loss, eye disease, severe otitis media, congenital heart disease, thyroid The child may also have mental retardation, hearing loss, eye disease, severe otitis media, congenital heart disease, thyroid disease, and gastrointestinal malformations. The diagnosis of Down’s syndrome is not difficult to make through its special facial and skin features. The main method to confirm the diagnosis is through laboratory karyotyping, which is used to detect the number and structural aberrations of chromosomes. Therefore, in order to prevent the birth of Down’s syndrome children, it is important to screen and diagnose high-risk factors before delivery. The blood of the pregnant woman is tested to determine the risk of the fetus having Down’s syndrome. If the results of the Down screening test show that the fetus is at a higher risk of having Down’s syndrome, further confirmatory tests – amniocentesis or chorionic villus test – should be performed.