Objective: To observe the clinical value of prenatal ultrasound in fetal ovarian cyst torsion. Methods: A total of 7 cases of fetal ovarian cyst torsion were diagnosed using ultrasound images and clinical data were retrospectively analyzed, follow-up of newborns after birth, analysis of the ultrasound characteristics of fetal ovarian cyst torsion and the significance of early diagnosis. Results: There were one case which was confirmed to be vaginal atresia after delivery were misdiagnosed. All six cases of cysts showed complex cysts before delivery, six cases were larger than 4cm in diameter, one case was less than 4cm in diameter, six cases of seven cases were confirmed to be pedicle torsion of ovarian cysts after delivery, ultrasound diagnosis of ovarian. The total accuracy rate of fetal ovarian cyst torsion by ultrasound was 85.7%. Conclusion: Prenatal ultrasound can identify the torsion of the fetal ovarian cyst, which has important clinical value. Complex cysts with a diameter of more than 4 cm are the key indicators for the diagnosis of fetal torsion by prenatal ultrasound.