In multiethnic countries, whether ethnic issues can be properly handled is related to the peace and stability of multiethnic countries. In the early days of the

founding of the Communist Party of China, the situation of ethnic problems was complex, facing the backward development of ethnic minority areas, the interweaving of ethnic and social contradictions, and the connection between ethnic problems and socialist revolution.The early spread of Marxist ethnic theory in China, for multiethnic China, was not only in terms of the liberation of the Chinese nation itself, but also in the area of coexistence of many ethnic groups. In reality, they all give strong answers. The Sinicization of Marxist ethnic theory has become the key to deal with ethnic issues in the early days of the CPC's founding. Based on the principles of national equality, national selfdetermination and national unity, the early Communists made a new interpretation of the combination of Marxist national theory and China's national conditions. Although there are limitations, these explanations also summarize the experience and lessons for the process of Sinicization of Marxist national theory, and lay a solid theoretical and practical foundation.