Ultrasound has been used in clinical practice for nearly 30 years, especially in obstetrics, where it is a very important auxiliary examination tool for fetal examination. Soon after B-ultrasound was applied to the clinic, many experts at home and abroad have conducted a lot of detailed research and elaboration work on the safety of B-ultrasound. And there are strict specifications for the setting of ultrasound instruments that should be used for clinical examination. According to all the current research data, there is not enough evidence to confirm that diagnostic ultrasound equipment can have significant biological effects on fetuses and other patients, and even if there is, the benefits of using ultrasound examinations carefully outweigh the disadvantages. At present, in regular hospitals, ultrasound doctors are required to undergo training before doing prenatal examinations, and doctors should always be aware of safety when doing fetal examinations. The ultrasound is a kind of physical energy, it definitely has the problem of safety dose, especially in early pregnancy examination should pay special attention to the early embryonic cells in the development period is relatively easy to be damaged, so the ultrasound examination in early pregnancy is best completed within five minutes, and the exposure time to the fetal eye should be shorter in pregnancy. Therefore, please try to choose a regular hospital for prenatal diagnosis of the fetus when you have an ultrasound examination.