The article analyzes the theoretical principles of teacher training in the system of postgraduate education for the introduction of play-based methods. It generalizes the scientific approaches of understanding the essence of the individual's readiness for the professional activity in general and pedagogical activity in particular. It is stated, that the readiness of a teacher for the professional activity is an integrative professional and personal phenomenon, the content of which is the integration of value-orientation, cognitive, constructive and reflexive components, and which is the result of long professional training and self-training of a specialist, new stage of his/her development. The peculiarities of the professional activity of elementary school teachers in modern conditions require the possession of play-based teaching methods, which are active in nature. Based on the analysis of the principles of the activity-based approach in education, it is stated, that they put forward their requirements for primary school teachers, including systematic formation of subjectivity as a teacher's ability to be an agent of childhood. The article analyzes the provisions of the integrative “learning through play” approach and the requirements for primary school teachers, which ensure the formation of students' learning experience with the help of the play resource. The work presents an author's understanding of the essence of the primary teacher's readiness to introduce the methods as an integrative personal-professional education, the system characteristics of a specialist, which determines his/hers ability to effectively use play-based teaching methods in the educational process and consists of value, cognitive and constructive components. Preparing a teacher for the introduction of play-based teaching methods is a complex and lengthy process that, in today's context, should take place in the space of postgraduate education