Abstract
The new round of curriculum reform requires the promotion on the development of students' core literacy, and how the core literacy of chemistry can take root in the chemistry classroom is inseparable from the guidance and nurture of teachers in the teaching process. The "Professional Standards for Secondary School Teachers" clearly stipulates that pedagogical content knowledge (PCK) is regarded as the professional knowledge of teachers. PCK is the core content of teachers' professional knowledge and an important guarantee for teachers to carry out teaching activities. Teachers’ PCK level is not only a direct measure of their teaching achievements, but also an important criterion for guiding novice teachers to become experienced teachers. The research subjects selected for this study are the middle school chemistry teachers in Yan'an City. By using the Delphi method to investigate the understanding of Yan'an middle school chemistry teachers on the core literacy of chemistry and to explore the PCK mastery of middle school chemistry teachers at different stages, it serves to deepen the Yan'an middle school chemistry teachers’ own knowledge and learning of PCK while help to promote the improvement of the teaching level and professional development of chemistry teachers in Yan'an middle schools. At the end of the paper, the relevant suggestions made based on the investigation of the chemistry PCK study of middle school chemistry teachers in Yan'an City on the core literacy of the chemistry subject will improve the overall building level of the middle school chemistry teachers of Yan'an City.