Objective To investigate the diagnostic value of using magnetic resonance imaging (MRI) and transabdominal sonography in antenatal placental adhesive disorders,to provide a theoretical basis for choosing different delivery ways.Methods 75 patients were assessed the placenta structure with MRI and transabdominal sonography.The patients were divided into two groups according placenta in the anterior and posterior uterus(41 cases in anterior group,34 cases in posterior group).Observed relationship between placenta and myometrium,compared imaging finding with pathological or clinical results.Results The sensitivity in diagnosis of placenta in the anterior uterine group was 75.0％ with MRI and 95.0％ for transabdominal Sonography (P＜ 0.05).The specificity was 90.1 ％ with MRI and 80.9 ％ for transabdominal sonography (P＞0.05).The sensitivity in diagnosis of placenta in the posterior uterine group was 95.8％ with MRI and 66.7 ％ for transabdominal Sonography(P＜0.05).The specificity was 90.0％ with MRI and 70.0％ for sonography (P＜0.05).There were significantly difference the imaging feature of uterine bulging,increased subplacental vascularity and dark intraplacental bands on T2-weighted images in placenta accrete group and nonplacenta accretegroup (P＞0.05).Conclusion Both sonography and MRI have fairly good sensitivity and imaging features for prenatal diagnosis of placenta accrete.Especially,MRI is an excellent tool for diagnosis of placenta accrete in the posterior uterine.