Over the years, the education sector has applied policies to build up and develop a contigent of core managers and teachers, including those in secondary schools. In fact, they have contributed greatly to training activities for school managers and teachers to serve the implementation of the General Education Program 2018. This article focuses on the development of secondary school core teachers in Thanh Hoa Province. Based on the theoretical framework of the Professional Standards for General Education Teachers, we conduct statistics and analysis of documents on the teaching staff in Thanh Hoa Province. The results show that the core teachers in secondary schools in Thanh Hoa Province acquire good qualifications and qualities, but their competences are not comprehensive. On the basis of analyzing the causes of the situation, we propose six solutions to develop the secondary school core teachers in Thanh Hoa Province.