The theory of "return to the Quran" is one of the most prominent epistemological foundations in contemporary Islamic thought, which aims to revive religious sovereignty and rebuild Islamic civilization by relying on the necessity of returning to the Quran. In the history of Islam, the abandonment of the Quran has been one of the most fundamental epistemological challenges of the Islamic nation, which has caused degeneration in the intellectual, cultural, and political spheres. In the intellectual system of Imam Khamenei (may Allah preserve him), this theory is a systematic response to the crises resulting from the separation of religion from the social sphere and governance. The present study, with a descriptive-analytical approach and using library resources, seeks to analyze the epistemological functions of this theory in the revival of the Islamic state. The scientific achievements of the research show that the theory of "return to the Quran" from the perspective of Imam Khamenei (may Allah preserve him) has fundamental functions in explaining the system of religious knowledge, rebuilding the humanities, Quranic education, and reforming social structures. This theory, by linking revealed knowledge and the political system of Islam, paves the way for the formation of a dynamic, justice-oriented, and civilization-building religious state. The research findings indicate that returning to the Quran is not only a guiding concept, but also a strategy for reviving Quranic rationality in the governance and cultural management system of Islamic societies.