The cerebellar transverse diameter at 34 weeks of pregnancy is between 3.86 ± 0.34 cm and 4.29 ± 0.26 cm. Fetal cerebellar transverse diameter an indicator to check whether the fetus is growing and developing normally, usually by ultrasound. The normal value of the test is related to the week of pregnancy, which is 2.16±0.16cm at 20 weeks, 3.86±0.34cm at 30 weeks, and 4.87±0.42cm at 40 weeks, with the specific value varying from person to person. It is recommended that pregnant women should go to the hospital in time for a detailed examination and communicate with the doctor in time when they find problems. Because the transverse cerebellar diameter is closely related to the development of the cerebellum, the development of fetal intelligence, and the development of the limbs, abnormalities should be standardized under the guidance of the doctor.