PCK is the experiential knowledge and skills acquired through classroom experience and it is the integrated set of knowledge, concepts, beliefs, and values that teachers develop in the context of the teaching situation. Research showed that experienced teachers have more integrated and developed PCK than beginning teacher (Lee, Brown, Luft, & Roehrig, 2007). But, how expert teachers develop their PCK? In this study, PCK is defined as a set of knowledge that teachers use to teach topic specific content. Five high school biology expert teachers participated in this study. They are interviewed to review their knowledge development processes. Concept maps are drew by the interviewer and the teacher together to identify expert teachers’ PCK components development and their relationships between each other. Then they were also interviewed about how they use these knowledge to design and teach a specific lessons based class observations or teaching video records. Based on interview and concept maps analysis, 5 explicit themes were identified: (1) Subject matter knowledge;(2) Student; (3) Pedagogy; (4) Class teaching; (5) Self-identity. Expert teachers developed their PCK components in different order and by different means, which were significantly driven by the teacher's personal study and work experiences. Implications and recommendations for teacher preparations and professional development programs were discussed.
