Objective To investigate the magnetic resonance imaging (MRI) of the diagnostic value of placenta previa, and provide the basis for assessing the prognosis. Methods Retrospective analysis of clinical data of 58 cases of patients with placenta previa, in which 26 cases of patients with placenta previa placenta accreta, all patients MRI and ultrasound, and the analysis and comparison of MRI and ultrasonography in the diagnosis of placenta previa compliance, the 58 cases of patients with placenta previa combined with placenta implantation whether grouped into placental implantation and control groups, comparing MRI imaging features two groups of patients, analytical specificity MRI imaging features of placenta previa placenta accreta. Results MRI in the diagnosis of placenta previa rate was 100.00%, of cases of misdiagnosis and missed diagnosis does not appear, ultrasound diagnosis of placenta previa rate was 79.31%, which missed 1 case misdiagnosed 11 cases. MRI and ultrasound of the former diagnosis of placenta previa compliance rate has significant difference (P<0.05). MRI imaging features of placenta accreta group and control group comparison, the lower uterine segment placenta implantation and control groups deformation or local doming, T2WI image appears low signal dark with implanted locally increased vascular flow void Movies were significant differences (P<0.05). Conclusion The diagnostic value of MRI for placenta previa was significantly greater than the ultrasound diagnosis rate, and patients with placenta accreta concurrent with characteristic MRI findings will help evaluate placenta previa prognosis for clinical interventions and provide timely basis.