本文透過個案,探討一種教師協作模式-課堂學習研究 (Learning Study) 的實踐共同體 (Community of practice)-如何協助老師解決智障學生學習數學所遇到的困難,從而提升課堂教學的成效。研究發現,課堂學習研究模式,使教師能透過前測及訪談,更具體掌握學習難點及教學焦點,而透過備課、觀課與修訂的教學循環能使教法更殝完善。實踐共同體的安排可使來自不同學校的教師進行跨校協作,有助特殊學校的教師提升教學技巧,並一同創造教學知識。本文建議此種模式可以推廣作為特殊教育老師一種持續專業發展的模式。This paper investigates the extent of a teacher collaborative model, Learning Study, in realizing the Community of Practice in special schools through a case study which helps teachers solve the learning problems of the mentally disabled students in the subject of Mathematics so as to enhance learning and teaching effectiveness. The findings indicate that the Learning Study approach enables teachers identify the learning difficulties and the teaching focal points from the pre-test and pre-lesson student interviews. During the co-planning, lesson observation and revising process of the teaching cycles, the pedagogies are further improved. The cross-school collaboration of the Community of Practice is able to help teachers in special schools enhance their pedagogical skills and create new instructional knowledge. This paper suggests that the collaborative model of Learning Study could be promoted as an approach for the continuing professional development of teachers in special schools. [Copyright of 香港特殊教育期刊 is the property of 香港特殊教育學會有限公司. Full article may be available at the publisher's website: https://sites.google.com/a/seshk.org.hk/seshk-org-hk/c_publication]