中国当前的低生育水平是广受关注的社会议题，本研究将其形成机制假设为一个外部有效性问题，尝试验证贝克尔妇女工资率提高→劳动时间延长→生育水平下降的人口增长模式变化理论是否适用于中国。研究采用CGSS2018、2021两期混合截面数据，假定家庭偏好在同一年内稳定不变，在控制个人特征、家庭收入等变量的情况下，验证中国单身妇女/夫妻平均工资率（子女价格）如何通过单身妇女/夫妻平均劳动时间（家庭分工）影响生育意愿。研究的创新点主要如下：第一，使用夫妻平均劳动时间描述家庭分工作为中介变量，有助于拓展原有影响机制研究；第二，假设中国土地财政发展模式下，居民基本需求成本高昂，劳动时间在平均意义上与工资率负相关。第三，基于产权理论视角提出解释新中国成立以来人口增长从“包袱”走向“红利”政策环境变化的理论假设。

回归结果发现，样本中单身妇女/夫妻平均工资率每降低1%，单身妇女/夫妻平均劳动时间延长0.21%，每100位妇女子女数量减少1-2个。工资率与劳动时间的负相关关系为解释中国当前低生育水平特殊性的核心内容，本研究认为其形成于地方政府廉价供给工业用地招商引资、高价垄断商住用地维持财政平衡的强制储蓄制度设计。在这一过程中，劳动者不断放弃闲暇以维持能够满足基本消费需求的收入水平，因而工资率继续上升对于闲暇的替代作用较弱，而禀赋收入效应更强。研究末尾对中国低生育水平的影响作为简要定性推论，并提出了方向性的思考与建议。

China's current low fertility levels are a widely discussed social issue. This study hypothesizes that the mechanism behind this is a problem of external validity, attempting to verify whether the demographic growth model change theory of increased female wage rates leading to extended working hours and decreased fertility levels is applicable to China. The study utilizes mixed cross-sectional data from CGSS 2018 and 2021, assuming that family preferences remain stable within the same year. Controlling for variables such as individual characteristics and family income, it examines how the average wage rates of single women/couples (the cost of children) impact fertility intentions through the average working hours of single women/couples (household division of labor). The innovative aspects of the study are as follows: First, using the average working hours of couples to describe household division of labor as an intermediary variable, which helps expand the existing research on influencing mechanisms; Second, it hypothesizes that under China's land finance development model, residents' basic needs are costly, and working hours are inversely related to wage rates on average. Third, from the perspective of property rights theory, it clarifies the policy environment changes that have shifted population growth from a "burden" to a "dividend" since the establishment of new China.

The regression results found that for every 1% decrease in the average wage rate of single women/couples, the average working hours of single women/couples increased by 0.21%, and the number of children per 100 women decreased by 1-2. The negative correlation between wage rates and working hours is central to explaining the particularity of China's current low fertility levels. This study attributes this phenomenon to the local governments' practice of supplying industrial land at low costs to attract investments and monopolizing expensive commercial and residential land to maintain fiscal balance through a compulsory savings system design. In this process, workers continuously sacrifice leisure to maintain an income level sufficient to meet basic consumption needs, resulting in a weaker substitution effect of rising wage rates for leisure and a stronger endowment income effect. The study concludes with a brief qualitative inference about the impact on China's low fertility levels and offers directional thoughts and suggestions.