在知識急速進步與變動的時代，知識共享與共構是未來的新趨勢。傳統師資培育偏重理論與知識傳遞的教學方式，固然有其優點，但面對未來知識社會的挑戰，師培課程也需要不斷進行反思與改進。為了改善傳統偏重知識傳遞的教學模式，本研究嘗試運用知識翻新(knowledge-building)理論於師資培育課程，並使用知識論壇平台(Knowledge Forum©)作為本課程的線上輔助學習環境。研究目的在讓師培生於課堂中實際進行體驗教學，並利用教室與線上知識論壇的學習環境進行大量教學反思，以期能幫助師培生發展更多元創新的教學信念，並且實踐於教學活動中。 研究對象為修習國民小學自然科教材教法的28位師資培育生，以個案研究法進行資料的蒐集和分析，資料包括：(1)整學期師培生在知識論壇平台上的互動與對話--使用知識論壇分析工具(Analytic Toolkit, ATK)計算學生於知識論壇平台進行知識建構的互動次數，亦使用社會網絡分析軟體(social network analysis)分析閱讀與回文訊息的流通情況，最後透過知識論壇學生的實際貼文內容，呈現師培生在平台上的互動情形；(2)師培生試教結束後在知識論壇的教學回饋內容--透過對教學回饋品質與教學回饋信念的質性編碼和兩階段相依樣本t考驗進行分析；(3)期初與期末的自我檢核表問卷--以質性分析軟體Nvivo進行開放式編碼，依據師培生對於問題的陳述內容進行編碼和兩階段相依樣本t考驗；(4)期初與期末的教學本質問卷--以質性分析軟體Nvivo進行編碼，依據師培生對開放性問題的陳述內容進行編碼和兩階段相依樣本t考驗；(5)期末試教反思問卷--計算師培生在試教活動中，教師中心與學生中心活動所佔時間的百分比，進行兩階段相依樣本t考驗，並根據師培生在教學設計、教法、教材和評量的反思內容，以貼文為分析單位，進行編碼和描述性統計。 研究結果顯示：(1)使用知識論壇平台有助師培生進行線上知識分享與自我反思；(2)透過知識翻新學習可以幫助師培生改進教學的回饋品質；(3)經由知識翻新學習讓師培生進行自我反思，可以幫助教學實務知識的發展；(4)經由知識翻新學習可以幫助師培生建立主動學習的教學信念；(5)讓師培生經由實際體驗教學與省思後，需要有更長的時間進行信念的內化，才能有效幫助師培生教學信念的實踐。 根據本研究結果，提出以下幾點建議供未來師資教育之參考：(1)教師可善用數位學習平台（如知識論壇）以輔助教學，促進學生想法的分享和改進；(2)營造開放自主的師資培育環境，可以建構多元的教學信念；(3)師資培育課程應提供更多實際體驗教學的機會，讓師培生檢視自我如何將教學信念付諸實踐；(4)課程革新應進一步思考如何促進教師教學信念與課程理念間的聯結，以協助教師在教學現場有效的落實課程。 / We are entering into a knowledge age, during which knowledge changes rapidly; accordingly, sustained knowledge sharing and constructing is essential. Although the traditional teacher education--that tends to emphasize more of the learning of educational theory than practical knowledge--has its advantage, teacher educators still need to reflect on and improve teacher preparation approaches continuously in order to face the challenge in the knowledge society. To this end, this study employed knowledge-building theory and Knowledge Forum© technology in a teacher education course. The purpose of this study was to help teacher-education students develop more informed science teaching beliefs by guiding them to effectively practice their teaching in classes, and to discuss and reflect on their teaching both in class and online. Participants were 28 teacher-education students who took a course about science teaching. Data sources (and analysis) mainly came from: (1) Teacher-education students’ interaction and discourse on Knowledge Forum (KF) (using the Analytic Toolkit to calculate the students’ frequency of activities on the KF platform; then, social network analysis was used to analyze the betweenness centrality and network density. Finally, examples of teacher-education students’ notes was analyzed to understand the interaction of teacher-education students in the KF platform); (2) Teacher-education students’ teaching feedback posted in Knowledge Forum (based on students’ answers, quantitative analysis was performed by means of paired-sample t tests); (3) An open-ended questionnaire that surveyed teacher-education students’ practical knowledge at the beginning and the end of semester was coded using key concepts as unit of analysis (quantitative analysis was performed via paired-sample t test); (4) A questionnaire with 6 open-ended questions that surveyed teacher-education students’ teaching beliefs at the beginning and the end of the semester was coded (quantitative analysis was performed via paired-sample t tests); (5) A questionnaire that surveys teacher-education students’ reflection on teaching practices (analysis was done by calculating the percentage of time on teacher-centered and student-centered teaching/learning activities using paired-sample t tests; and in addition, students’ texted answers were analyzed qualitatively). The results showed that: (1) using Knowledge Forum was helpful for teacher-education students’ sharing of their knowledge and reflection on their teaching; (2) Engaging in knowledge building could help improve teacher-education students’ teaching feedback quality; (3) Engaging in knowledge building could help teacher-education students’ development of their practical knowledge; (4) After engaging in knowledge building for a semester, teacher-education students developed more constructivist-oriented learning beliefs; (5) It was time-consuming to help teacher-education students develop more informed teaching beliefs. Building on the results, this study made the following suggestions: (1) Teachers should make good use of online learning platforms (e.g., Knowledge Forum) to facilitate students’ idea sharing and improvement; (2) Teacher education programs should help foster an open learning environment, in order to foster the development of multiple teaching beliefs; (3) Teacher education programs should provide teacher education students with more opportunities for teaching practice and for reflection on their teaching beliefs; and (4) Curriculum reform should try to better relate curriculum development and teachers' beliefs development.