John Dewey was an American philosopher, psychologist, and educational reformer who was known to be a leading proponent of American pragmatism. He worked in many fields such as philosophy, ethics, and pedagogy. Dewey’s thought has influenced education in Japan and China. In this paper, I introduce Dewey's life experiences and consider Dewey’s ideological characteristics at each stage of his career. On this basis, I focus on the important parts of Dewey's educational theory and the theory of educational essence. In this section, based on Dewey's original works, Democracy and Education (1961) and Experience and Education (1938), I concretely clarify Dewey’s theory of educational essence. This section consists of three parts: namely the significance of education, the aims of education and the connection between education and experience, and the value of education. In the first part, we can see that Dewey claims education is not preparation for life; education is life itself, and in addition, education is growth. In the second part, I demonstrate that Dewey suggests that the purpose of education is growth, Specifically, I illustrate Dewey’s understanding of growth, Dewey emphasizes that growth is supposed to have two aspects, that is, horizontal growth and vertical growth. In addition, Dewey clarified the distinction between the active and passive sides of experience. Finally, in the last part, I demonstrate how Dewey understands the value of education.