The purpose of this study is to understand the elementary school teachers’ curricululm implementation experiences in an In-School-Teacher Learning Community. To achieve the above purpose, the following research question is formulated. 1. How is the experience of Elementary school teachers’ curriculum implementation in an In-School-Teacher Learning Community? For finding out answers to above research question, a grounded theory that is one of the qualitative methodology was performed. The specific methods utilized were intensive interview, literature review, analysis of related materials. The research finding are as follows. First, in open-coding, conceptualization and categorization of experience of participating in teacher learning community were tried and finally 70 concepts, 32 subcategories and 17 categories were derived. In axial-coding stage, category analysis was performed by the paradigm model and the process analysis was tried by the time flow. Based on the central phenomenon named ‘collective research - circulation structure of collective practice’ as a result of the category analysis, ‘needs for professional growth’ and ‘necessity of cooperation’ appeared as causal conditions. The contextual conditions were ‘change of education policy’ and ‘school situation’. Intervening conditions were ‘the role of principal and supportive environment’, ‘characteristics and assignment of members’, ‘communication and common goal’, ‘spontaneity’ and ‘autonomy’, and ‘teacher cooperation'. The action・interaction strategies on the central phenomenon were ’operation and participation strategies’, ‘role sharing strategies’, ‘instruction implementation strategies’, ‘affective domain strategies’, ‘instruction collegiality formaton’ and ‘competence of curriculum implementation’s growth’, and ‘school culture to study together’. As a result of the process analysis, successive connections according to the flow of action・ interaction strategies appeared in three stages of ‘recognition and attitude formation’, ‘attempt and adjustment’, and ‘overcoming and maintenance’. This study analyzed the structure and flow of teachers' ability to perform curriculum through cooperative teacher learning of In-School-Teacher Learning Community. Finally, in selection coding, it was discovered a core category of ‘constructing a reflective discussion structure on teaching practice’ through the outline of the story and moving forward together with the improvement of curriculum implementation capacity.