Abstract: It is important to study the placental transfer of drugs for the drug safety of pregnancy. Many in vitro techniques were applied in this field. There are three models of in vitro placental transfer of drugs，the perfused placental model with whole placenta，the BeWo cell model used for studying the transfer crossing trophoblastic cells，and the placental tissue model which is a useful and simple model developed by the placental tissues at different pregnancy stages. These models were appropriately used to investigate the drug distribution in placenta，which is important for the clinical treatment with fetal safety and drug discovery for pregnant women.

Key words: Placenta, Maternal-fetal exchange, Cells, cultured, Models, biological, Models, theoretical