Fertility postponement plays an important role in the decline of China’s fertility rate. Putting housing prices and timing of birth into the same research framework will help us to explore the role of housing prices in the micro-resource allocation of families, so as to take effective measures to curb the unreasonable rise of housing prices and achieve the purpose of adjusting the population size and structure. However, most of the existing literature on housing prices and fertility studies the effect of the housing price rise on the fertility rate from a macro perspective. A few studies from the micro perspective also only deal with the influence of housing choice and the number of houses on family fertility decision-making, but have not analyzed the mechanism of housing prices on the birth time. This paper discusses the influence of the rising housing price on families’ timing of first birth by establishing a theoretical model of family fertility utility and using the micro data of China General Social Survey（CGSS）. The research results show that the housing price significantly delays the time it takes for families to have their first child:（1）The housing price rise changes the family budget constraint, that is, the housing price rises by 1%, the first birth time of families is delayed about 1.05 years; （2）The housing price mainly has a great influence on the birth time of middle income families, but has no significant influence on low income families and high income families; （3）For families with 1 suite, the birth time is obviously delayed, but the housing price has no significant impact on families with 2 suites or more; （4）The high housing price has a significant impact on the decision-making of family birth time in eastern provinces and cities, but its impact on central and western provinces and cities is not statistically significant.

The research conclusions of this paper has obvious policy implications: Under the current situation that the annual decline of the fertility rate seriously restricts the economic and social development, the single population policy cannot fully play the role of regulating the population and boosting the fertility rate, and it must cooperate with other policies and supplement each other to play a real role. As the “contraceptive” to delay the family birth time, the high housing price needs to control the housing price level on the basis of the active population policy, reduce the housing consumption pressure of young families, and make room for the budget for the birth of young families. Moreover, the social security system can further provide certain guarantees for women’s fertility. Only in this way can the trend of continuous low fertility rate be reversed, the pressure brought by the aging society be alleviated, and new driving forces be brought to the economic development.