Schools are the most important places for promoting energy conservation and carbon reduction education. Most studies focus on cultivating cognition, literacy and attitudes of energy conservation education in schools and cites, along with student confidence in its effectiveness. However, there are few studies to explore the ways how students integrate what they have acquired in class into their daily activities on a larger scale and in a contextualized situation. Taking a school fair as an example, this study aimed to identify inner contradictions when the school engaged in transforming from a traditional fair to an innovative green fair. This study adopted the Activity Theory as an analytical frame work to analyze data from a four-year collaborative school-university research project. The results found four layers of contradictions. After several rounds of in-depth discussions and alignment in the change laboratory, the teacher community reconceptualized the objectives of the activity. The school solved these contradictions and organized a green fair with energy saving and carbon reduction.