As a special phenomenon of human society, language is always accompanied with human beings. And it has always been in a dynamic and open ecosystem. It gives us a lot of inspiration. We must observe and discuss the interrelation and mutual influence between language and its surrounding environment as well as social reality while studying language. In view of this, this paper adopts the method of comparative analysis, and focuses on three aspects from the perspective of sociolinguistics, which include language learning and national identity as well as individual identity, language vision and language planning, the promotion of Mandarin and the protection of endangered languages. And finally it comes to the conclusion. Language has the dual functions of national identity and individual identity. There is no fundamental conflict between the promotion of mandarin and the protection of minority languages in China. China's language policy and language planning should be based on China's national conditions. We should not only consider China's needs of current economic, political, and cultural development, but also combine its goals of long-term development and the individual future development.