“All Under Heaven(tian xia)” was once a concept that concentrated the Chinese world view. In ancient China, the Chinese defined the world order through the concept “All Under Heaven”, and “All Under Heaven” was also a concept that implies their values. But Chinese intellectuals facing the Western powers in the early 20th century sought to abandon the concept of the “All Under Heaven.” For them, “All Under Heaven” was a relic of the feudal era and only an obstacle to the construction of a modern nation-state. But now, in the twenty-first century, Chinese intellectuals are calling for a new concept of "All Under Heaven." Zhao Tingyang's “system of All Under Heaven” is a representative example of this new discourse. Zhao Tingyang is digging into the weaknesses of a modern nation-state system based on a Western world view to present new possibilities for “All Under Heaven.” For example, he points out the concept of “individual”, which is the basic unit of the modern nation-state system, and the problems that arise. The conflict between sovereign states is also a serious problem of the modern nation-state system. To overcome these problems, Zhao Tingyang proposes the concept of “All Under Heaven,” while presenting “All Under Heaven” as a higher concept beyond individual nations and individual individuals. It is insisting that the concept of such a higher concept should go beyond the modern nation-state system based on particular individuals and nations. Of course, Zhao Tingyang's claim cannot simple be denied. This is because the contradictions of the modern national state system based on Western philosophy are very serious. However, since the modern nation-state system that “All Under Heaven” has to go beyond is a “reality,” we first need to consider more fundamentally what the basis of the modern nation-state system is and whether it is possible to go beyond it. This paper will examine what is the inner core of the modern nation-state system and the possibility of overcoming the modern nation-state, and then explores what "All Under Heaven" means.