The number and sex composition of children a woman has are important factors that affected the fertility of women．This present study used the parity and sex progression model，together with the China’s 2000 population census data to analyze China’s fertility. The results showed that, women generally gave birth but a large proportion of women only gave birth to one child throughout their lives．The reproductive behavior reflected the son preference through the parity and sex of children a woman had．There was a certain first- birth sex selection among women in city and town．A large proportion of women continued to give birth after having a girl, and the child born was more likely to be a boy than a girl．While most women in city or town no longer gave birth after having a boy, a large proportion of women in village continued to give birth after having a boy，who had almost no sex selection．This article used data from a certain region in 2019 and that women who have only one girl were much more likely to give birth than women who have only one boy．The analysis can obtain enlightment on the curreat second-child reploductive behavior．
