The Three-child Policy, implemented by the Chinese government in 2021 to boost fertility and address negative population growth, entails considerable long-term unpredictability and affects the allocation of preschool teacher resources. This study uses the cohort-component method to project the population growth of young children (ages 3-6) from 2024 to 2050, based on the Seventh Population Census data and estimates the demand for preschool teachers in China by 2050. Using parameters such as preschool enrollment rate and teacher-child ratio, the prediction analysis indicates that (1) there will be three models of population growth: the low-, medium-, and high- levels and the medium-level model will reach a low point in 2031, a peak in 2044, and then decline again; (2) there will be six levels of preschool enrollments in China during 2024-2050 and will show consistent changing trends; and (3) the demand for preschool teachers in China will very likely go through three major stages: first decrease, then increase, and then decrease from 2024 to 2050. And, there will be a surplus of preschool teachers for a long time by 2050. The findings estimate the medium-level model of young children's population growth and predict its long-term impact on preschool teachers' demand. They will inform China's policymaking regarding teacher preparation and resource allocation for early childhood education. This case also provides suitable lessons for other countries facing similar challenges.