Abstract: The Tang Dynasty is an important stage in the process of the development of China's unified multi-ethnic country and its frontier. The Tang Dynasty adopted a series of jurisdiction and governance measures in the frontier areas, while maintaining close diplomatic contacts with overseas countries. Cultural exchanges were the shining point of this period. From the angle of culture, this paper holds that the Tang Dynasty constructed the psychological identity of honesty and credit by respecting the political and cultural customs and practices of ethnic groups in its foreign exchanges. Affirming the role of religion, whether it is the primitive religious beliefs of ethnic groups or Taoism, Manichaeism and Buddhism, they pay attention to realizing and serving their realistic purposes with the help of the power of gods in their contacts. In addition, emphasizing the radiation of Confucian culture to achieve the role of Tao to teach and mix, it can take timely measures to open up a good communication situation with literary and artistic interests and hobbies. Through cultural participation and interaction, it will add luster to the formation and development of China's unified multi-ethnic country, and add bricks and tiles to the fine inheritance of China's good-neighborly, friendly and harmonious diplomacy. The rich and colorful characteristics of cultural exchanges also show the charm of culture in foreign exchanges.