This study explores the reflection and dialog feedback of preservice teachers (PTs) in a one-semester chemistry teaching design and practice course with the aim of improving their situated and dynamic pedagogical content knowledge (PCK). Using a collective case study method, reflections and dialogs from 18 PTs across six teaching cycles were analyzed. The research results indicate that teaching reflection focuses on five themes: the diversity of student situations, the functionality of teaching contexts, the consistency of teaching content, the construction of teacher‒student dialog, and the progression of subject practice activities. The reflection of the PTs strengthened meaningful teaching content and corresponding specific skills, and effective dialog feedback provided external evaluation standards. The reflection prompted teachers to evaluate from multiple perspectives and levels and provided important insights to promote the development of situated and dynamic PCK. This study concludes with a discussion of the practical implications and potential for future research to develop a situated and dynamic PCK for PTs.