Abstract: The proposal of free preschool education policy marks the transition of China's public early childhood education service system from universal access and affordability toward tuition-free provision. This study applies the Multiple Streams Theory to analyze the policy formation process of free preschool education. The results reveal that, (1) the Problem Stream emerged from developmental metrics indicating the universal and inclusive development of preschool education, socially salient focusing events, and feedback from administrative interventions; (2) the Policy Stream materialized through persistent advocacy by National People's Congress deputies and Chinese People's Political Consultative Conference members, research-driven contributions from experts, and local pilot initiatives; and (3) the Political Stream crystallized through policy directives from Party and state leaders, the governance philosophy of building a fertility-friendly society, and public sentiment demanding that children receive proper care and optimal early childhood education. The dynamic integration and profound coupling of these three streams converged to open the policy window for free preschool education. Future policy implementation should activate each stream's distinctive functions while leveraging their synergistic momentum, adhere to principles of equity and quality, address challenges in pluralistic service provision, and sustain policy advancement, ultimately establishing a new paradigm of high-quality balanced development in early childhood education.

Key words: free preschool education, multiple streams theory , generative logic, policy implications