Research objective: To study the problem of teacher training and the model of teacher training following the competency approach. Research method: through selected documents that are closely related to the research task, we conduct retrospective analysis, summary, systematization of theories related to teacher training and the model of teacher training following competency approach, groups of documents are: (i) in Vietnam, we are interested in the innovative content of the 2018 general education program issued by the Ministry of Education and Training of Vietnam. ; (ii) In 5 countries where education is developed, namely the US, Germany, Australia, France and the UK, we look at how they have developed a source of quality teachers. Research results: The study suggests how the Vietnamese education sector should do: (1) Raise awareness about the role and importance of professional development for secondary school teachers in the context of educational innovation in Vietnam; (2) Renovating the direction of the Ministry of Education and Training for the training of secondary school teachers; (3) Develop a process for training secondary school teachers in accordance with the proposed competency framework to meet the requirements of the 2018 general education program in Vietnam; (4) Directing the renewal of training forms, programs, contents and methods for secondary school teachers; (5) Completing the coordination mechanism to manage professional capacity building activities for secondary school teachers