Objective To explore the expression and localization of aquaporin 11(AQP11) in human term pregnancies with oligihydramnios, and its role in amniotic fluid balance.Methods We studied 55 patients who underwent elective cesarean sections, consisting of 25 patients with isolated oligohydramnios and 30 with normal amniotic fluid volume.Immunohistochemistry and reverse transcription polymerase chain reaction were employed to determine the expression and localization of AQP11 in the amnion, chorion and placenta.Results AQP11 protein was detected in expressed in the full-term pregnant women`s amnion, chorion and placenta.The expression in the amnion was positively correlated with amniotic fluid amount;the expression in the placenta was negatively correlated with amniotic fluid amount.The expression increased in the chorion with different amniotic fluid amount.Conclusion AQP11 plays an important role in regulating amniotic fluid balance.