Objective: The aim of this study was to analyze the fetal magnetic resonance imaging (MRI) findings of seven cases of obstetric mirror syndrome (OMS). Materials and Methods: The fetal MRI results of seven cases of clinically/pathologically confirmed OMS were retrospectively analyzed, including fetal hydrops, placental edema, association with related malformations, etc. Results: The seven OMS fetuses all displayed multi-site edema and two cases were associated with placental edema. Other associated malformations included fetal sacrococcygeal teratoma (SCT, 1/7), Rh-defect (D) caused immune hemolysis (1/7), fetal growth restriction (FGR, 2/7), twin-twin transfusion syndrome (TTTS, 2/7), and placenta chorioangioma (1/7). OMS can increase maternal and fetal morbidity and mortality, so early diagnosis of this disease could have important significance in providing the appropriate treatment protocol and improving the clinical outcomes. Conclusions: Fetal MRI was an important supplementary means of obstetric ultrasound, which could qualify fetal hydrops-associated malformations, characterize the nature of the tumor, and assess the situations of the heart and lung development of fetal edema simultaneously.