Objective:To characterize the expression of BCL2/adenovirus E1 B 19 k D protein-interacting protein 3（BNIP3）in placenta and mitophagy induced by BNIP3 in regulation of apoptosis in preeclampsia. Methods:The expressions of BNIP3 and cleaved-caspase3 protein were detected in placenta from normal pregnancies and pregnancies complicated with preeclampsia by Western blot.HTR8/SVneo were used as the preeclampsia cell model and treated with hypoxia/reoxygenation（H/R）. RNA interference technology was performed by using BNIP3 specific small interfering RNA（si RNA）;Western blot was used to identify the expression of BNIP3 after RNA interference. The experiments were divided into two groups:si-NC group and si-BNIP3 group

then treated with H/R

the production of reactive oxygen species（ROS）within cells was detected by 2’

7’-dichlorodi-hydro-fluorescein diacetate（DCFH-DA）and flow cytometry was used to detect the apoptotic cells. Results:The expression of BNIP3 in placenta from preeclampsia was lower and the expression of cleaved-caspase3 was higher（P=0.015

P=0.019）. Within the preeclampsia cell model

the knock-down of BNIP3 by si RNA significantly increased the production of ROS and activities of apoptosis in HTR8/SVneo（P=0.022

P=0.038）. Conclusion:Impaired mitophagy induced by BNIP3 within placenta participates in the excessive production of ROS and excessive apoptosis.