An artist, Oh Yun(1946~86)'s theory of people's art during his final period is summed up in his essay 'Expansion of Artistic Imagination and World' (1985). Emphasizing the mystic and traditional characteristics of Oh Yun's artistic oeuvre during his final period, some critics focus on Oh Yun's experience of medical treatment and shamanistic custom at Jin Do island, and his belief in Jeung San Do, the dao of Jeung-san, the Ruler of the Universe. However, they forget the practical intention and implication of his theory of art during his final period, which aimed to overcome the contradiction of revelation itself. Oh Yun's essay criticized the loss of artistic imagination and the ignorance of traditional culture that resulted from the elevation of science to a religion, and insisted that the stereotyped idealism, scientism and elitism in art should be overcome in order to recover the full reality in realism and to continue traditional cultures. The essay is comprised of 18 paragraphs. Oh Yun criticized monochromatic art, conceptual art, hyper-realistic art, objet d'art, and neo-dadaist art, saying that they were simply mechanical forms of modern art derived from scientism and a fetishistic lens culture. In addition, he criticized naturalism in art, which had continued as a tendency in the development of western art, for the same reason. He pointed out that even the world of realism had been diminished by elite stereotypes and diagrams. He declared the need to overcome the imitation of shells or stereotyped propaganda, and recover full realism, which seems to have started with a reflective examination of current problems in 'Reality and Utterance', in which he participated. Especially, he thought that universality and the extension of full realism could be achieved by building on the views of traditional cultures, which is meaningful. This logic is same as the theory of epic theatre that Bertolt Brecht(1898~1956) has developed under the ancient Greek masque and Pieter Bruegel the Elder(1525~69)'s story-like picture style. The universality of realism and the extension of acquisition to include incantation art, rather than move toward incantation art, is what Oh Yun intended to propose in 'Artistic Imagination'. This attitude is same as Bertoh Brecht's aesthetic viewpoint in the 1930s. But regrettably, Oh Yun's style wording, which seems covert and far-sighted, is often misunderstood as 'mysticism'. In the flow of people's art in the 1980s, Oh Yun was a traditionalist in a narrow sense, and an realist in a broad sense. However, his critical mind, which comprehends tradition and reality, was attempting to expand universality and extend full realism, and this attempt found many sympathizers and had an influence on the next generation of people's artists, such as "Levee" which is field-centered, to which we should pay attention. This means that while their works thought about 'tradition', we should be careful not to connect them with 'aesthetic conservatism' or 'classical art'. This is the why the meaning of Oh Yun's theory of art during his final period should be closely examined again.