In this commentary, I interpret Xinying Yin and Gayle Ann Buck's collaborative action research from a social-cultural perspective. Classroom implementation of formative assessment is viewed as interaction between this assessment method and the local learning culture. I first identify Yin and Buck's definition of the formative assessment, and then analyze the role of formative assessment in the change of local learning culture. Based on the practice of Yin and Buck I emphasize the significance of their "bottom up" strategy to the teachers' epistemological change. I believe that this strategy may provide practicable solutions to current Chinese educational problems as well as a means for science educators to shift toward systematic professional development.