正當性（legitimacy）是統治階層自覺提出，並經被統治者認可的行使權力的根據。若從歷史脈絡加以考察，正當性也是政治文化（political culture）研究的重要對象。在中國中古前期（約三世紀中至六世紀末）南北分裂、政權更易頻繁的格局下，統治階層多試圖藉用各種資源與途徑，論證政權的正當性；對正當性的追求，是其時政治文化的一個顯著現象。本文析論南北朝晚期追求政權正當性的實態，從禪讓書寫、「王氣」論述，及隋文帝（541－604）對政治忠誠和「天道」的態度與舉措等幾個側面，描繪南北朝晚期政治文化中的一個重要元素，並為中國中古前期許多相關課題，提供一些有益的觀察與思考。

The idea of legitimacy denotes the right of governing and practicing power; it is consciously offered by ruling groups and accepted by the subjects. In terms of its historical context, legitimacy is an important research object for the studies of political history, history of political thought, and political culture. The separation of regimes framed the political environment of early medieval China (approximately from the mid-3rd century to the late-6th century), and the transfers of imperial power occurred frequently in both the north and the south. Under this circumstance, all the ruling groups were forced to seek ways to claim their political legitimacy. The pursuit of legitimacy was indeed a significant phenomenon at that time. This essay elucidates the contemporaries' search for legitimacy through analyzing the writings of abdicating, the discourses of ”kingly qi,” and the Emperor Wen of Sui's attitudes toward and reactions against the issue of political loyalty as well as the idea of the ”Heavenly Way.” By combining the discussions of abstract ideas and historical context, this essay may contribute to the studies of legitimacy, political culture, and early medieval Chinese history.