Abstract: The cervix is a barrier between the uterus and vagina，it is the organizational structure with dynamic change, the structure of cervix has a progressive change during pregnancy, including softening, shortening, funneling, effacing, dilating and postpartum repair, which is called "cervical remodeling". Any congenital malformation or injury of cervix will cause cervical incompetence，result in premature birth or abortion. A series of physiological and pathological changes of cervix before pregnancy, during pregnancy are described in this paper.