This article analyzes the transformation in Vietnamese political thought from the concept of “state” associated with the “Son of Heaven” in Confucianism to the concept of “nation” in Nguyen Trai's ideology. The focus is on comparing Confucian thought, which regards the “state” as a part of the governance system of the “Son of Heaven,” with Nguyen Trai's perspective, who expanded the notion of “state” into an independent national ideology, affirming Dai Viet as a sovereign nation with its own identity. The study clarifies the inheritance and development of Nguyen Trai's thoughts on “state” and “nation” regarding national sovereignty, the concept of “governing the state,” the philosophy of “humanity and righteousness,” and his approach to diplomatic relations. Using historical and logical methods, the article demonstrates the evolution of Nguyen Trai's thought while illuminating his unique contributions to the construction of the national ideology of Dai Viet. The expected results affirm the timeless vision of Nguyen Trai and provide insights into the formation of the concepts of independence and sovereignty in Vietnamese history.