The Song and Yuan Dynasties is an important period in the development history of feudal ethnic relations in China, and it is also an important development stage in the process of multi-integration of the Chinese nation. During this period, the Han nationality interacted with other ethnic minorities in various ways, such as war, envoy, mutual market, intermarriage, etc., which not only promoted their own development, but also accelerated the process of ethnic integration by understanding Professor Fei Xiaotong's theory of "the pattern of multi-ethnic integration of the Chinese nation" and using the method of literature collation and analysis, systematically analyzed the process of multi-ethnic integration of the Chinese nation in the Song and Yuan Dynasties and analyzed the manifestations and reasons of ethnic integration in this period. Since the Song and Yuan Dynasties were a period of development from the confrontation between the Han nationality and the minority regime to the unification of the Yuan Dynasty, we need to study the process of the pluralistic integration of the Chinese nation in this period in two stages. The first stage is the Song Dynasty, which mainly guides the period of confrontation between the Northern Song Dynasty regime and the Liao, Xixia, Jin and other minority regimes. In this period, the process of multi-integration of the Chinese nation is characterized by ethnic integration in areas ruled by ethnic regimes. Qidan, Tangut and Jurchen are deeply influenced by Chinese culture in politics, economy, culture and social customs. The second stage is the Yuan Dynasty, during which the prominent feature of the process of multi-ethnic integration of the Chinese nation is ethnic integration under the unified situation, and unprecedented economic integration, cultural integration and ethnic integration have been achieved between the Han nationality and ethnic minorities under the Yuan Dynasty. It is not difficult to find that the process of the Chinese nation from pluralism to integration is gradually completed, and it is a situation from regional reunification to final reunification. This is the process of multi-integration of the Chinese nation in the Song and Yuan Dynasties. The ethnic minorities in Song and Yuan Dynasties had a strong national consciousness and cherished their own culture. With its advanced culture, political system and mode of production, the Han nationality has played a core and leading role in the process of the pluralistic integration of the Chinese nation. Judging from the process of the pluralistic integration of the Chinese nation in the Song and Yuan Dynasties, the pattern of the pluralistic integration of the Chinese nation was formed mainly through the following ways: first, complementary and mutually beneficial inter-ethnic economic ties; Second, the integration and recognition of ideology and culture; Third, ethnic migration and mixed residence; Fourth, inter-ethnic marriage; Fifth, reuse outstanding talents of all ethnic groups.