Introduced in the 1980s, the concept of content pedagogical knowledge (PCK) has grown significantly in the field of mathematics in the next decades. From the outset, PCK assessment has attracted the attention of researchers. After reminding the origin of the concept, two assessment approaches (static vs dynamic) of PCK are put into perspective. Given the feature of preschool, PCK assessment of teachers practicing at this level is developed in the second part of the paper. Finally we will see that the question of PCK is intrinsically linked to that of teachers' professional development. In this domain, recent research opens new and interesting perspectives, especially in the field of assessment.