Objecitve To explore the different manifestations of placental abnormality in MRI examination and to measure the thickness of the lower segment of the uterus, it provides a reliable basis for clinical selection of different delivery methods. Methods The clinical data of 183 patients with clinical and postoperative pathologic confirmed placental implantation and threatened uterine rupture between January 2016 and August 2017 were retrospectively analyzed.MRI routine was performed to summarize the diagnostic results and MRI imaging findings. Results 1.MRI diagnosis of adhesion type, implantable type and penetration type placenta is 76%, 94%, 100%, diagnostic sensitivity 82.4% and specificity 81.0%. 2. It was found that the MRI diagnosis of the thickness of the anterior wall of the uterus was 83.6%, misdiagnosis 16.4%, and the sensitivity of the precursors was 89.2% and the specificity was 100%. 3. Two cases of placenta, one in the giant placenta and one case of grape placenta. Conclusion MRI examination was used to assess the type of placenta implantation and the thickness of the lower segment of the uterus, accurate identification of placenta implantation depth, location, scope and beneficial guidance and discovery of aura rupture, It provides effective operation method for clinical practice and has high promotion value.