Mou Chung-san's "the realm of unity", as an aesthetic category, deserves special attention. "the realm of unity" takes "goodness" as the cornerstone, and "truth is beauty is goodness"(unity category) as the connotation. It has the characteristics of no image, that is, truth is no truth image, beauty is no beauty image, and goodness is no goodness image. The theory of Mou Chung-san is not the same as that of Wang guo-wei and Feng you-lan. "The realm of unity" is artistic (aesthetic), but it is not limited to art (aesthetic), while Wang Guo-wei's "realm" is mainly artistic (aesthetic); "the realm of unity" is life, but it is not limited to life, while Feng You-lan's "realm of life" is mainly life. "The realm of unity" is the unity of life and art, and it is the development and promotion of Wang Guo-wei's "realm" and Feng You-lan's "realm of life" theory.