Population decline,aging and lowest-low fertility constitute the population crisis of the 21 st century. The"fertility deficit"and lowest-low fertility are the roots of the crisis. Discussing issues regarding the stability of relationship between fertility intentions and fertility,the changing fertility intentions,the impact factors of fertility intentions,fertility deficit,and the influence of family policy on fertility intentions,this paper outlines the development of theoretical and empirical research on fertility intentions since the 1980 s,and points out the existing problems of research on fertility intentions in China. China’s childbearing intentions has been at a very low level,which signals a birth crisis and requests serious attention.