Pedagogical Content Knowledge (PCK) is the core field of teachers’ knowledge research and a key element in measuring teachers’ professionalism. Previous studies have shown that PCK is contextual in nature. Therefore, investigation on the connotation and elements of PCK should fully reflect the teaching context. However, little has been done to study business English teachers’ contextualized PCK. This study aims to fill this gap by examining the PCK of business English teachers in the context of Content and Language Integrated Learning (CLIL) through interviews, questionnaires and concept mapping. The findings indicate that business English teachers’ PCK includes the following elements: Knowledge of Contextualized Objectives, Knowledge of Teachers and Students, Knowledge of Instructional Strategies and Knowledge of the Integration of Content and Language. Significant or moderate positive correlation has been found among these elements which together constitute the concept of business English teachers’ contextualized PCnK. It is proposed that Business English teachers’ PCK is different from traditional language teachers’ PCK as their teaching context is interdisciplinary and compound in nature. This study reveals the characteristics of PCK elements of Business English teachers, and can help teachers construct or improve their own contextualized PCK and inform the transformation of novice teachers to expert ones.