Teacher collaborative learning is key in teacher professional development. Yet, how teachers learn in cross-cultural professional development settings remains largely unexplored. This paper examines the case of a Chinese mathematics teacher who learned through addressing various challenges when teaching in an English school in a China-UK exchange program. A praxeological perspective was used to analyze the data, including lesson plans, classroom observation notes, and post-lesson meetings. Results showed that collaboration and adaptation helped the teacher address the obstacles generated by cultural differences. The analysis revealed the difficulties the teacher encountered and how the mathematical and didactic praxeologies implemented evolved and helped overcome these challenges, broadening her mathematics knowledge for teaching. Finally, the implications of the case study on teacher collaborative learning in cross-cultural settings are discussed.