Abstract: Multilingual families in Xizang are a product of the promotion of national lingua franca，social and economic development，and the interaction and integration of local ethnic groups. They are naturally a place for forging a strong sense of Chinese national community. The multilingual families in the Shannan region of Xizang were taken as a sample and a questionnaire survey based on judgmental sampling were conducted. The statistical results show that most of the adults in multilingual families have a strong command of Putonghua；they not only recognize the national identity that comes with Putonghua，but also well inherit their ethnic languages ，becoming bilingual or multilingual. Education and urban-rural differences are important factors affecting their Putonghua proficiency. In the process of learning Putonghua，they expect to receive assistance including textbooks and other teaching materials，online resources，thematic training，employment opportunities，and qualification examinations. In order to forge a strong sense of Chinese national community and promote the common prosperity of all ethnic groups，relevant authorities should make a good top-level design for the promotion of Putonghua，compile graded and progressive Putonghua training materials，enrich the forms and types of training，and strengthen the inheritance and protection of disadvantaged minority languages.

Key words: Chinese national community, Xizang, multilingual family, Putonghua promotion, language competence, Putonghua proficiency