Based on the data of China General Social Survey (CGSS) from 2013 to 2018, this paper studies the effect of the ratio of housing price to income on the fertility intention of couples at the childbearing age. The empirical study shows that fertility willingness among couples at the childbearing age is greatly stifled by the ratio of housing price to income under the two-child policy. After dealing with the endogeneity problem by means of instrumental variable method and various robustness tests, the results are still robust. Heterogeneous analysis shows that the ratio of housing price to income has more negative impacts on the unmarried, on people with lower well-being, on those renting and owning just one house, and also on people living in eastern China. In addition, the ratio of house price to income significantly reduces people’s willingness to have baby boys. Therefore, the government should actively regulate and control the real estate market, advocate the concept of fertility in the new era, and improve the social pension security system, so as to improve the fertility intention of couples at the childbearing age, and to regulate sex ratio at birth.