Ultrasound examination during pregnancy includes observation of the size, position and echo of the placenta. There are two types of placental echogenicity expressions, one is homogeneous and the other is inhomogeneous. If the placenta is not homogeneous, the main consideration is that there may be foci of calcification or uneven distribution of local blood flow in the placenta, which does not mean that there is a problem with the placenta, as many pregnant women have uneven placental echo. As long as the other ultrasound indicators, such as the size of the placenta, the thickness of the placenta and the distance between the placenta and the inner cervical opening, are normal, it is not necessary to pay much attention to the placental echogenicity. However, we should pay attention to whether there is a combination of posterior placental hemorrhage, if the placenta is inhomogeneous due to posterior placental hemorrhage, we should consider the possibility of placental abruption.