Abstract: During normal pregnancy，placental trophoblast cells have the ability to invade-like tumor cells. However，unlike tumor invasion，trophoblast cell invasion to the maternal deciduas is under highly control and is a normal physiological behavior. The overinvasion and inadequate invasion can lead to such pathologies of pregnancy as choriocarcinoma，miscarriage and preeclampsia，respectively. Nowadays，the mechanisms responsible for trophoblast cell invasion to maternal deciduas remain unidentified. Evidence indicates that the maternal decidual microenvironment exerts important influence over trophoblast cell invasion. The further study will be helpful to understand the pathogenesis of pathological pregnancy.

Key words: Deciｄｕａ, Ｔｒｏｐｈｏｂｌａｓｔ ｃｅｌｌ, Ｉｎｖａｓｉｏｎ