Fetal arterial blood flow of 3.5 to 5.5 at 24 weeks of pregnancy is considered normal. Fetal arterial blood flow is an ultrasound test to assess the intrauterine condition of the fetus by examining the umbilical artery peak systolic flow rate (S)/end diastolic flow rate (D) ratio, which decreases with increasing gestational weeks. Fetal arterial blood flow between 3.5 and 5.5 is normal at 24 weeks of gestation, and an S/D ratio between 2 and 3 is normal near term. When the value of fetal umbilical artery blood flow is high, it may suggest the possibility of intrauterine hypoxia, but also combined with the PI value (pulsatility index), RI value (resistance index), fetal heart rate monitoring, etc. to comprehensively assess, when it is clear that there is fetal hypoxia, we should terminate the pregnancy as soon as possible, but also to do a good job of neonatal resuscitation rescue preparations, in order to ensure the safety of mothers and infants.