Abstract: In the late Ming and early Qing Dynasties, the exploration of forest resources in Qingshui River Valley became the mainstream of the development of Qingshui River Valley. A market system and production system around timber trade had formed and attracted various people to join in the resource competition in the commodity market, which built a multiethnic society in the middle and latter period of Qing Dynasty. Sanqiao People were the marginal group who were active in the commodity market process in the region. Sanqiao People's migration, settlement and livelihood showed that once the remote mountain area was in commodity market, its population supporting capacity and tension would expand and amplify. Thus, it would not only form a full tolerance multiethnic society, also the sustainable development in this region would be guaranteed in some degree in the process of commodity market. In the past 400 years, the relatively open timber market and its economic benefits were the root cause of sustainable development in Qingshui River Valley.