To identify whether placental volume, T2 dark band volume, and cervical length measured by MRI correlate with massive hemorrhage (MH) in patients with placenta accreta spectrum (PAS) disorders. A total of 163 pregnant women with PAS underwent preoperative MRI examination were divided into MH group and non-MH group. The placental volume, T2 dark band volume, and cervical length of PAS patients were measured and evaluated their ability to identify MH in patients with PAS. Patients with MH had a significantly larger placental volume, larger T2 dark band volume, and shorter cervical length than patients without MH (all P<0.001). Multivariable logistic regression showed that placental volume (>890cm3), T2 dark band volume (>35cm3), and cervical length (<30mm) were significant independent risk factor in identification of MH. In all PAS patients, a positive linear correlation was found between placental volume and amount of blood loss (r=0.527), and between T2 dark band volume and amount of blood loss (r=0.642), and a negative linear correlation was found between cervical length and amount of blood loss (r=-0.597). When combined with the three MRI indicators, the sensitivity and specificity in identifying cases at high risk for MH were 91.638% and 94.051%, respectively, with area under the curve (AUC) of 0.923. The placental volume, T2 dark band volume, and cervical length might be used to predict MH in patients with PAS.