Placeness is the fundamental factor for ethnic villages to develop tourism. This study focused on the placeness reconstruction of mountainous ethnic tourism villages and the influencing factors of their strength and weakness level. We used the fsQCA analysis method to explore the antecedent condition combination of placeness strength and weakness of ethnic villages, which consists of physical geographical environment, social structure and function, residents' emotional value and behavior, enterprise operation and production, and tourists' participation, experience, and behavior. The results show that: 1) There is a complex relationship between the placeness of ethnic tourism villages and their antecedent conditions, and individual conditional variables cannot constitute sufficient conditions that affect the level of placeness reconstruction. It is affected by a combination of the factors. 2) There are eight combination paths of factors affecting the placeness level of ethnic tourism villages, with an overall consistency of 0.900 and an overall coverage rate of 0.890. The path with the optimal original coverage and consistency is combining residents, communities, businesses, and tourists. 3) There are four types and eight combinations of paths that affect the placeness reconstruction process and level of mountainous ethnic tourism villages, namely traditional place atmosphere driven, host-guest interaction driven, tourism production driven, and value co-creation driven. Together, these paths explain how conditional factors affect the placeness reconstruction of mountainous ethnic tourism villages under the mechanism of diachronic and synchronic perspective of placeness reconstruction. This study theoretically enriches the content of placeness research, which provides some references for the further exploration of the unique characteristics of mountainous ethnic tourism villages and the sustainability practice of tourism areas.