本研究從迷思概念為線上小組合作的共同學習成品之觀點，分析在同儕合作共構知識下迷思概念的發展過程與消長關鍵，並藉以深入揭露線上小組合作的學習內涵。研究場域是在一個探究「大氣科學」範疇的線上討論區，其中的學習活動是以小組合作進行，同儕間一同進行長達六週的探究式學習。在研究分析上，本研究看重同儕合作的對話過程，包含了以單篇文章為單位的「迷思概念」和「探究行動」、及文章與文章之間為單位的「迷思概念發展和同儕合作互動之間的動態關係」。研究結果的發現有三：第一、除了指認出同儕間探究「大氣科學」研究範疇「地溫」專題的主要迷思概念、迷思概念座落的討論片段與主題；第二、發現在小組合作學習下引發迷思概念消長的五個關鍵，包含了參考資料驗證的釐清、同儕指認下的終止、實踐經驗下的修正、同儕認同下的延展、事過境遷下的混沌與遲滯。同儕間互為主體性的相互接應，是影響迷思概念發展的重要條件。第三、本研究企圖對線上小組合作知識共構的分析方法有一些啟發，及對於概念學習的教學提出建議。

This study attempts to investigate the meaningful learning of online-group knowledge co-construction by identifying the misconceptions, tracking the developmental trajectories of misconceptions, and recognizing the critical moments in the trajectories of misconceptions. Instead of using the ＂product＂ perspective that the contributions for leading a misconception are accounted by the number of their postings, we here adopt the ＂contextual-process＂ perspective that considers the whole temporal trajectories of misconceptions taken place and focuses on the group members’ interaction. In particular, we analyze our data by identifying misconception and inquiry action of each single post, and figuring out the dynamic relationship between the developmental trajectories of the misconceptions and the group peer’s interaction. The results show that there are 56 posts involve the misconceptions and can be categorized to five themes, in which three themes are aware to have the positive learning effects after group discussions, one has negative effect, and the remained one does not cause any effect for learning. We also discovered the five critical moments: ＂sharing and justification＂, ＂recognition＂, ＂practical knowledge＂, ＂identification＂, and ＂confusion and hesitation＂. Finally, we further consider ＂intersubjectivity＂ is the important key for the development of and reconsider the meaning-making of the trajectories of misconceptions in online-group knowledge co-construction. And some methodological consideration and teaching strategy about online-group knowledge co-construction was discussed.