With the comprehensively advance of globalization, people have to change their traditional ways of living, their traditional ideas, and people have to construct their national identity. The characteristic of national identity in Cross-border ethnicity is complexity, fuzziness and instability. Once the national identity of Cross-border ethnic groups is low, it will affect their national emotion, then endanger social stability of frontier region, even the whole country. Clarifing the psychological mechanism of national identity in Cross-border ethnic groups, is not only a urgent realistic task, but has a long-term strategic significance. Through 4 studies, this project implements the following research objectives: ①The project divides national identity into culture identity and civic identity, then compiles the national identity questionnaire of Cross-border ethnicity. ②The project explores the mediation of ethnic identity, Muslism identity in perceived discrimination and national identity. ③The projects clarifies the effect of lay theory of ethnicity on national identity. ④Through 4 years’ tracking survey, the project explores the effect of management system and policy, economic development level and ethnical policy on national identity. Then the project try to establish the database of national identity in Cross-border ethnicity, timely grasps the dynamic construction of national identity in Cross-border ethnicity. The results of research will help governmental department to perfect the ethnic policy, guide the propaganda department to carry out the education of national identity.