Objective To explore the errors and differences of different initial incisions in three-dimensional ultrasound examination of fracture deformity. Methods Using GE Voluson e8 ultrasonic diagnostic instrument, the circular hole and metal long hole were reconstructed by static three-dimensional imaging mode, and the three-dimensional images were compared with the actual measured hole values. Seven fetuses with cleft lip deformity and three specimens were reconstructed by three-dimensional ultrasound, which were compared with the crack width images of the initial incision of fetal cleft lip in parallel and vertical directions respectively. Results The longitudinal diameter of the hole is 30 ~ 90mm long when the distance between the probe and the metal, and the ratio of the initial tangent of the longitudinal hole is 25 ~ 95mm to the actual value is 0.90 ~ 1. 10. The diameter distance of the round hole is between 50 and 75 mm, and the ratio of the initial parallel distance of 50 to 90 mm to the actual value is between 0.90- 1. 10. The ratio of the rest to the actual distance value is less than 0.90. Fetal cleft lip or fissure with different widths was initially cut, and different data were obtained in different cleft palate parallel to and perpendicular to the long axis of the fissure. Paired T test showed that the data obtained in the direction perpendicular to the fissure after initial cutting was larger. Conclusion only when the probe and the object are imaged at 50 ~ 75 mm can they approach the real image. When the distance is 30 ~ 50mm and 75 ~ 90 mm, the fracture image reconstructed by 3D is thinner than normal, and the fracture width is smaller.