Utilizing the 2014 Hukou reform as a quasi-natural experiment and applying the difference-in-differences design to the 2019 National Population and Family Dynamic Monitoring Survey data, this study examines the impact of Hukou reform on fertility intentions and behaviors of migrant women and their mechanisms in China. The results show that the reform significantly increased fertility intentions and behaviors, particularly among those who got married after the reform and those with low educational levels. Further analysis reveals three mechanisms: improved fertility rights and benefits through free prenatal and newborn health services, enhanced employment protection via maternity leave policies, and transformed attitudes towards reproduction. This study expands the research perspective on how fertility support influences fertility decisions, offering important policy implications for Hukou reform and migrant population development.