Down’s screening is mainly to screen for congenital disorders of the fetus during pregnancy, which allows for early diagnosis and early treatment to avoid the birth of malformed children. The risk of congenital open neural tube abnormality, trisomy 21 and trisomy 18 is the main risk value of Down’s syndrome. In general, no special treatment is needed for low-risk cases, and the chances of malformations are very low. In the case of intermediate and high risk, the next step of testing is required, such as perfecting amniocentesis, testing for chromosomes, etc. Patients should go to the hospital for Down’s syndrome screening on an empty stomach, at around 15-20 weeks of pregnancy.