近年來，隨著實驗教育三法與「偏遠地區學校教育發展條例」通過後，越來越多位處偏鄉的公立學校思考採行實驗教育理念進行創新轉型，其中進行混齡教學是一項主要採取的策略。然而在公辦公營的體制內國民小學實施混齡教學，學校校長應該如何妥善因應可能遇到的問題，進而採取教育創新的作法加以經營，是值得深入探究的。本文透過會議紀錄等文件、實地觀察蒐集資料，藉由研究者敘說的方式進行探究，對象為一所因應學生數驟減且參與教育部委託的創新混齡實驗教育計劃，探討該校由公立小學轉型三年中實施混齡教學的緣由、成員間之影響與發展情形、且分析其困境與作法。研究發現學校在實施歷程中，教師積極投入參與、透過協同教學與教學共享、教師之間與學科領域專家持續進行對話，成員間的正向影響進而發生教師文化之改變。活力國小採取「固本體驗」的理念實施實驗教育課程，根據學生學習表現調整教學方式，然而該校面臨的困境在於行政負荷與教育評鑑、編輯混齡教材、因應實施混齡所產生的空間問題、與如何適當招收學生。學校教師之間彼此互信相互陪伴、家長的信任與交付，成就教師為提高學生學習成效努力而不斷前進的穩定力量。

In the past few years, since the government's declaration of the Three Acts for Experimental Education and the Act for Education Development of Schools in Remote Areas, more and more state schools in remote areas have been considering or deciding to innovate and transform the schools' management through the strategy of multi-grade teaching, as based on the experimental ideas. However, it is worthwhile to discuss how the school principals manage and deal with the problems or difficulties under the state school system while taking multi-grade teaching as an approach. The data collected in this study came from the meeting minutes and field observations in a state school that has been participating in an innovative multi-grade experimental education program supported by the Ministry of Education for three years. Using a narrative inquiry approach, the researchers investigated why and how the school has been taking the approach of multi-grade teaching, discussed the mutual influences and development among colleagues, and analyzed their difficulties and problem-solving strategies. According to the research findings, the school implemented the innovative multi-grade experimental project under the predicament of declining student enrollment. During the implementation process, the teachers actively participated in the project through collaborative teaching and sharing, and they have maintained continuous professional discourse with subject experts; as a result of the positive mutual impacts among the participants, changes in teacher culture have been taking place. Based on the concept of striking a balance between the basic learning subjects and the experimental courses, the teachers adjusted their teaching methods according to the pupils' learning performance. However, the school faced the difficulties of high administrative load and educational evaluations, the compilation of multi-grade materials, the requirement of additional spaces for multi-grade teaching, and the proper ways for the admission of pupils. Finally, there are some factors that may help keep the school moving forward, such as the mutual trust and company among schoolteachers, parents' trust and confidence, as well as teachers' working hard to enhance pupils' learning performance.