Abstract: This study explores the influence of multiculturalism on group information processing and cultural attachment of Tunpu people. In experiment 1, the group reference paradigm was used to investigate the ethnic information processing of Tunpu people. Experiment 2 used the cultural attachment paradigm to investigate the cultural attachment of Tunpu people to their own ethnic group and the surrounding ethnic groups.The whole study shows that the cultural exchanges of all ethnic groups have enabled the Tunpu people to accumulate rich multicultural experience, construct the Tunpu people's identity with their own ethnic group and other ethnic groups or nationalities, and condense the positive emotions of the Tunpu people in their own ethnic group culture and other ethnic groups or ethnic cultures. While blending with other local cultures, Tunpu people also stubbornly maintain their own cultural uniqueness and strong ethnic identity.