Over the last two decades, `Pedagogical content knowledge(PCK)` has become a powerful lexical item in the subject matter educational community. And it has been considered as providing the theoretical foundations of the new reform for teacher professionalism. However, in spite of the vast number of studies on PCK, there seems no significant progress. This critical review reveals that the root of the problem lies in the fact that they have failed to find an endogenous conceptual framework of education. The main problems and recommendation for further research are summarized as follows: Firstly, the criterion of relevance of PCK has not fully paid attention to. So it is suggested that the multiplicity and vagueness of the social demand for school and teacher should be reflected before making any effort to improve teacher`s PCK. Secondly, the value of education has been reduced into that of subject matters. The value of subject matters should be reconceptualized as a means to provide the educational experience and enthusiasm rather than as an ends which needs to be internalized. Finally, the dualistic distinction between the content knowledge per se and pedagogical content knowledge is criticized. Because that distinction is derived from objectivism which is now in severe criticisms. And the way to deal with that problem is suggested in terms of `Educational epistemology` grounded on `Endogenous theory of Education`.