Whether an education policy can effectively improve teaching ultimately depends on the interpretation, transformation and support at the school level. To clarify the micro-level mechanism of “policy text – school-level transformation – teacher development” in this process, this study adopts a mixed-methods research design, combines questionnaire surveys and semi-structured interviews, draws on a large-scale regular tracking survey dataset on education quality, and adopts stratified sampling to select 68 public schools, 426 frontline teachers, 68 principals and 136 middle-level managers as samples. The data are analyzed using SPSS 26.0 and NVivo 12. The results show that: the depth of schools’ rational interpretation of policies has a significant positive predictive effect on the appropriateness of school-level policy implementation; the transformational leadership of principals and management teams is the core mediating factor for the flexible transformation of policies; four types of organizational support, namely instrumental, teaching-research, emotional and institutional support, can significantly alleviate the occupational burden brought by policy implementation, and improve teachers’ acceptance of reform and initiative in professional practice; the moderating effect of two-level leadership runs through the entire path from “implementation” to “empowerment”. Heterogeneity tests indicate that in medium-sized schools with complete teaching-research echelons, the coupling between policy transformation effectiveness and teacher development gains is higher.
