Abstract: As an integral part of the river-sea ecosystems and the local societies, the " Dan” (boat people) is drawing much more scholarly attention for understanding the critical significance of the historical changes in southeast China. In the local society and regional culture along the coast of Fujian in the Qing Dynasty, the " Dan” was not only a historical " ethnic group” or a " base and marginalized society”, but also a lifestyle, a field of social actions, a discourse of status, or a label of cultural classifying. Moreover, by breaking of variously defined " boundaries”, the roles played by the " Dan” deeply reflected the structure of the local society and its fluidity since the Ming and Qing Dynasties. By situating an inscription of the Jiaqing period in the context of institution, custom, identity, and ethnicity, this article will discuss the interactions of the " Dan” and the local society of Fuzhou, and try to approach a certain historical " thick description” through the interpretation of local document in the field.