Preterm birth is the second leading cause of death among children under 5 years old in the world, and it has become one of the health indicators to measure a country. Effective preterm birth screening can improve the prevention and treatment of preterm birth.Because of the advantages of non radiation, wide applicability and simple operation, ultrasound has been used as a means of clinical evaluation of preterm delivery.This article reviews the application of ultrasound in the evaluation of cervical pregnancy in the prediction of preterm birth.