Introduction: Polyhydramniosus is a pathological condition characterized by excessive accumulation of amniotic fluid, usually more than 2100ml. It is associated with numerous fetal anomalies and causes maternal complications due to overdistension of the uterus. An AFI(Amniotic Fluid Index) exceeding 24cm constitutes the diagnosis of severe polyhydramniosus. Case Report: The patient was a 25-year-old woman G3P1D1Ab1 referred at 28 weeks of gestational age with chief complaint of respiratory distress due to severe polyhydramniosus. Amniotic Fluid Index(AFI) had been reported to be 35cm from 24 weeks of gestational age. The patient was admitted into the hospital and amniocentesis was done nine times. About eight liters of amniotic fluid was evacuated. Her chief complaint decreased gradually and at last she delivered a baby boy at 32 weeks of gestational age due to preterm labor. The apgar score was 8-10 and no abnormality was observed. Conclusion: Doing amniocentesis, we postponed the delivery for about 5 weeks so that we could achieve fetal lung maturity.