Under the county-based school management system, effective implementation of education policy depends on rational cognition, sincere participation and full support from front-line teachers. Based on the 10-year study of the "School Union and Mobile Teaching" policy of S County in Hubei Province, it's found that the intertwined connection between various formal and informal institutions constitutes a real institutional situation and constraints that affect the flow of front-line teachers. As rational actors, front-line teachers often deconstruct educational policies based on their own situations and make choices to maximize their interest, and participate in the implementation of the policy in a different identity. The differences in teachers' responsibility in policy implementation have led to shifted policy goals, and many public teachers have become bystanders of policies. Given regional differences, urban-rural differences, and inter-school differences, it is important to capture information on how teachers "do policy". Only by understanding the real needs and behavioral expressions of teachers in specific situations can we understand the complexity of the implementation process of educational policies, and thus provide valuable information for constructing effective teacher incentives and improving the effectiveness of policy implementation.