Objective This paper studies the influence of childbearing on women's career development and discusses the opportunity fairness of women with different numbers of children in career development. Methods The purpose sampling method was adopted in the study,and the women of childbearing age who had one child and made a clear decision on the second child were selected as the investigation objects. The influence of number of children on women's career development was analyzed by binary logistic regression model and the moderating variables were tested. Results In the past three years,the percentage of career advancement in women with one child(40.79%)was higher than that of women with two children(29.02%);In the women whose education was postgraduate and above,the percentage of career advancement in women with one child(64.71%)was higher than that of women with two children(41.03%);In the two groups of women in different post,there was statistical significance in the difference of career advancement(P<0.001). It had greatest difference in senior managers;In foreign/joint venture enterprises,there was the largest difference in the percentage of career advancement between the women one child and two children(26.47%). After controlling human capital and structural factors,the career advancement opportunities of women with two children were significantly less than those with one child,and the former were 45.1% less likely to be promoted. Conclusions Under the different classifications,there is obvious difference in the career advancement of the two groups of women. Women with different numbers of children have a certain impact on their career advancement. Measures should be taken to help professional women balance the relationship between work and family.