The Chinese education system issued a series of policies to encourage educators to explore science, technology, engineering, and mathematics (STEM) education and selected a number of schools and educators as pioneers of STEM education. Through the education policy implementation framework, this qualitative study explores eight pioneering educators’ interpretations of STEM education, their knowledge of STEM education policies, and how they transform their understanding into practice. The results show that the pioneering educators hold a similar understanding of the definition of STEM education and how STEM education should be conducted. However, they adopted diverse STEM practices due to their different academic backgrounds, administration roles, school environment, available resources, and personal abilities and interests. They displayed tension and confusion over their own STEM practices and requested official guidance. The tension may have emerged from the conflicts between the top-down policy operation system and the place-based, bottom-up nature of STEM education. Further, STEM policies played a positive role in increasing educators’ openness and confidence in trying new STEM education strategies; however, they could not influence how educators performed their STEM practices. The educators proposed four kinds of policies to support STEM practices. This study highlights the importance of including teachers’ ownership and agency while drafting STEM education policies and proposing practices. The implications for better STEM education policy design and implementation are discussed.