〔Abstract〕 Objective To evaluate the clinical diagnostic value of ultrasonography in patients with incomplete mediastinal uterus in mid and late pregnancy. Methods From April 2018 to April 2019, 45 patients with middle and late pregnancy of incomplete mediastinal uterus diagnosed and treated by Beizhen maternal and child health and family planning service center were included in this study. All patients were examined by ultrasound, and the results and advantages of ultrasound diagnosis were discussed. Results Among the 45 patients, 43 patients with incomplete mediastinal uterus were diagnosed by ultrasound, and the accuracy rate was 95.56%. The ultrasonic image showed that the cross section of the upper segment of the uterine cavity was "dumbbell" in 38 cases, accounting for 84.44%. The myometrium of the upper part of the uterine mediastinum and the uterine fundus was thickened, with a thickness of 2.2 ~ 5.3 mm, and the average thickness was (3.47 ± 0.61) mm. There were 12 patients with thickening or deformation of placenta at the bottom of uterus, accounting for 26.67%. Among all the patients with incomplete mediastinal uterus in the middle and late pregnancy, 13 patients delivered normally, accounting for 28.89%; The remaining 32 cases were delivered by cesarean section, accounting for 71.11%. There were 42 cases with abnormal fetal position, accounting for 93.33%, including 23 cases with transverse fetal position, accounting for 51.11%; Fetal hip circumference was 9 cases, accounting for 20.00%. Conclusion The accuracy of ultrasonography in patients with incomplete mediastinal uterus in middle and late pregnancy is high.