Objective To explore the application of MRI in diagnosing the placenta implantation. Methods To evaluate the performance of MRI and make a statistical analysis, the MRI images of 20 patients with placenta implantation confirmed by operation from January 2014 to December 2014 were retrospectively analyzed. Results MRI showed 12 cases with uteroplacental interface thinning or focal defect (P=0.002), 13 cases with the interruption of uteroplacental interface inner layer (P=0.012),11 cases with the disappearance of normal pear-shaped uterus (P=0.007),7 cases within traplacental low signal bands(P=0.016),6 cases with increased subplacental vascularity (P=0.260),1 case with placental infarction (P=0.452), 10 cases within homogeneous placenta signal intensity (P=0.640).The MRI features of placenta implantation with diagnostic value were uteroplacental interface thinning or focal defect, interruption of uteroplacental interface inner layer and disappearance of normal pear-shaped uterus. The overall sensitivity and specificity of MRI in diagnosing PIA were84% and 84%, respectively. The uteroplacental interface thinning or focal defect were the most valuable MR performance in diagnosing PIA (the accuracy was85%). Conclusion The overall sensitivity and specificity of MRI in diagnosing PIA were84% and 84%, respectively. The uteroplacental interface thinning or focal defect were the most valuable MR performance in diagnosing PIA.