Abstract: Rural revitalization in underdeveloped areas faces practical challenges such as weak resource endowment, insufficient endogenous momentum, and difficulty in sustaining external support. The core issue lies in the absence of a synergistic mechanism between external inputs and endogenous development. Based on the theory of Neo-endogenous development, this study constructs an analytical framework of "resources-participation-identity-innovation" and takes L County in Y Province as a case to explore the county-level logic of promoting rural revitalization in underdeveloped regions. The study finds that L County has clarified the direction for sustainable resource use by introducing external resources and revitalizing internal stock; established a participatory and cooperative development model to build a multi-agent governance structure, thereby stimulating rural governance vitality; fostered a public spirit in ethnic villages through the relocation-based poverty-alleviation initiative, achieving organic solidarity within the community and shaping the consciousness of the Chinese national community; and, through digital empowerment, innovated local resources and restructured multi-dimensional governance elements, breaking the "low-efficiency dormant state" of indigenous resources and realizing a "self-sustaining innovation" model for rural development.

Key words: rural revitalization, underdeveloped regions, county-level logic, neo-endogenous development