戰國後期諸子思想有匯合趨勢，學術與政治都呈現「求同」的傾向，然而先秦諸子學說仍得以延續，差異如何在趨同中存在？漢初被視為雜家的重要著作《淮南子》，試圖建立一個天人相參，貫通天地的思想體系，將「道」定位為宇宙創生的源頭，以陰陽五行為天地運行原則，在這個架構下，儒法各家之異，得以被容納與吸收。政治與學術的「求同」，並沒有消除各家差異，反而在諸子思想皆能保存的「存異」之下，得以成就整體。本文以兩層論詮釋《淮南子》如何結合「求同」與「存異」，於政治制度「求同」，一方面以國君居樞紐之位，行「無為」之治，強調同一與秩序；又於社會結構「存異」，申論萬物各得其宜，各安其所，要求統治者順應萬物之性，順勢而為。正視差異並保存之，才能體道與行道，「求同」必需在「存異」的基礎上才得實現。《淮南子》論述「同／異」關係，不僅只是漢初施政所需，也涉及儒道會通的議題，於思想史具有重要意義。

In the late Warring States period, there was a trend toward the convergence of the thoughts of various schools. Both academic and political studies exhibited a tendency to "seek the sameness." However, the diversity of pre-Qin scholars' doctrines persisted. This raised the question of how differences among these doctrines could exist amidst this convergence. Huainanzi (淮南子) is regarded as an important work of the Mixed school (Zajia雜家) from the early Han dynasty. It aimed to establish an ideological system in which heaven and man were interrelated, and continuity existed between heaven and earth. This book positioned "Dao" as the source of the universe's creation, and used Yin and Yang and the Five Elements as the principles governing the movement of heaven and earth. Within this framework, the differences between Confucianism and Legalism could be accommodated and absorbed. "Seeking the sameness" in politics and scholarly research did not lead to the elimination of differences among schools. Instead, it is only through "preserving the differences" that all schools of thought can maintain their ideas, thereby achieving the wholeness of the schools. This article employs a two-level theory to explain how Huainanzi combines "seeking the sameness" and "preserving the differences." On the one hand, the book pursued unity in the political system by placing the monarch in a pivotal position to practice "inaction" governance, emphasizing unity and order. On the other hand, it preserved differences in the social structure, arguing that everything has its own suitability and its place. The ultimate goal is for rulers to comply with the nature of all things and act in accordance with prevailing trends. Only by acknowledging and preserving differences can a ruler understand and practice "Dao." "Seeking the sameness" can only be realized through "preserving the differences". The relationship between "sameness and difference" discussed in Huainanzi was crucial not only for governance in the early Han dynasty but also for integrating Confucianism and Daoism. Consequently, Huainanzi holds great significance in the history of Chinese thought.