In order to promote the overall growth and development of children, early childhood educators may benefit from specialised professional development programmes that are designed to improve their abilities and pedagogical techniques. Understanding the exact influence that professional development has on the well-being of children is something that needs to be investigated, despite the fact that its significance is well acknowledged. In the context of early childhood education in China, empirical research is required because of the complex links that exist between teacher professional development, teacher-child interactions, self-efficacy, and the well-being of preschoolers. The purpose of this research was to investigate the relationships between early childhood education teacher professional development, teacher-child interactions, self-efficacy, and the well-being of preschoolers via the use of quantitative analysis. As a result of professional development, the results demonstrate improved relationships and self-efficacy, with considerable mediation occurring via interactions between teachers and students. An emphasis was placed on the moderating impact that teacher expertise has in relation to development consequences. 230 Chinese early childhood educators participated in this study, which highlights the significance of providing opportunities for professional development for educators. The research provides valuable insights that may be used to improve educational practices by illuminating the linkages that exist between professional growth, relationships, and well-being.