本研究透過專業學習社群提昇國中數學教師對話式形成性評量實務，從而促進學生數學學習成效。其具體作為在於協助教師整合教學與評量於一堂課中，從而即時探查學生的學習進展與需求，做出立即回饋幫助學生數學學習；本研究也分析學生的數學學習成就是否受益於教師形成性評量實務的改進，以期對教師專業成長理論有所貢獻，研究者一方面以Mehan（1979）的課堂架構理論分析數學課堂師生對話現況以及教師在學習社群中對話式形成性評量實務進步的歷程，另一方面以單因子共變數分析瞭解實驗組學生的數學學習成就是否顯著高於對照組學生。研究發現：一、在學習社群初期，參與教師仍是以低層次問題進行師生對話，沒有給予學生充分待答時間；二、以三階段循環模式運作學習社群可以有效幫助教師改進對話式形成性評量實務，以高層次問題探查與釐清學生想法，逐步引導學生數學學習；三、學生的數學學習成就獲益於教師對話式形成性評量實務的改進。最後，本研究報告學習社群對於教師個人專業成長的影響、提出教學建議以及後續研究的建議。

This study aimed to improve mathematics teachers' formative assessment practice in junior high schools through a teacher professional learning community. Teachers learned to integrate instruction and assessment in a lesson in which they examined students' learning progress by questioning and then gave students immediate feedback accordingly to push students learning forward. In addition, this study examined whether or not students' learning achievement in mathematics benefits from the improvement of teachers' instruction. The researchers applied Mehan's (1979) theoretical framework to analyze teacher-student discourse in mathematics classrooms and to inspect the progress of participating teachers' questioning/feedback. Students' mathematics learning achievement in the treatment group was compared with that of students in the control group in terms of one-way ANOVA. Results suggested that: (1) In the beginning, the participating teachers tended to use low-level questions to conduct teacher-students discourse and did not allow students enough time to answer the questions; (2) While the teacher professional learning community was operated in terms of a three-stages and cyclic model, teachers' formative assessment practice was improved effectively. Participating teachers began to probe and to clarify students thinking by posing high-level questions with an aim to guide students learning step-by-step; (3) Students' mathematics learning achievement benefited from the development of their teacher's teaching. This study also reported the influence of the learning community on the participating teachers' personal professional learning and provided suggestions for teacher instruction as well as suggestions for subsequent studies.