This study explores the question of how ethnic groups were assimilated by the Imperial State to be placed under the administration of the central government and how their ethnicity changed during this process of nationalization. This paper studies the case of the Yi ethnic group in Bailu Ying of Mianning county, Sichuan Province in China. The ancestors of Yi people in Bailu Ying lived on Mount Daliang before the Wanli reign of the Ming Dynasty. In the early period of the Ming Dynasty, the government had set up Ningfan Garrison on the river valley on the west side of Mount Daliang. By the late Wanli Period, the garrison was consistently being attacked by the indigenous people in the area. In order to quell the resistance, the Imperial Court recruited Yi people as soldiers to guard the garrison. Afterwards, a new settlement of the Yi tribe in the Bailu Ying River valley emerged, and in the process the Yi people’s livelihood was transformed from herding and fishing to agriculture. In the early Qing, the Yi people in Bailu Ying were further integrated into the Imperial system with the inclusion of chieftains in the imperial governing body. However, up until the later years of the Qianlong reign, the Yi maintained relative autonomy in terms of its tribal settlement, power structure and cultural integrity. Later, with the arrival of new Han migrants, the introduction of the Baojia system, and the promotion of Han culture and education, the Yi group in Bailu Ying gradually lost its independence and began to be assimilated into the national identity, leading to the formation of Shuitian (rice field) Yi ethnicity. The case of the Shuitian Yi shows that the survival strategy of tribal minorities from the mountains did not necessarily follow the pattern of ‘avoiding becoming part of empires’, as suggested by James C. Scott, nor were these ethnic people always slow and passive in integrating with empires. On the contrary, the acceptance of the imperial rule was a survival strategy that helped to creating new ethnic groups while also consolidating frontiers for the Ming and Qing Empires.