Starting from the perspective of cultural assimilation, this paper analyzes the different aspects of Tibetan Buddhist selection, acceptation, and acculturation of Indian Buddhism, including Tibetan society’s intentional introduction of Buddhism, translation, the establishment of theory of translation, taking part in the reconstruction of sacred geography, and outward dissemination of Tibetan Buddhism. Further, under the wide view of localization of religion, the paper discusses the prospective acculturation between Tibetan Buddhism and Han Chinese Buddhism, based on the adaptation between Indian culture and Tibetan culture. It aims to prompt the real understanding of the place of Chinese culture which is created by all of ethnic groups living in China in the history of world culture.