Based on literary sources and scientific articles on pedagogy and also guided by the results of our own pedagogical experience we substantiated the importance of the teaching program implementation through the content lines of the different subjects through the project activity realization during the education period in order to form the key competencies responsible for students’ socialization, active personal formation and ease of adaptive period of teenagers’ transition into adulthood. The research emphasizes on the dominant role of the cross-cutting project activity as a method of knowledge obtainment in the research process during the implementation of the concept of the New Ukrainian school and the importance of the project activity organization form and method correction.