基于全国县域层面数据构建三维识别框架对欠发达县进行精准识别，研究发现：中国现有528个欠发达县，其空间分布呈“西密东疏”格局、功能属性呈“多维重叠”特征，在经济发展、财政能力等方面与发达县的差距较大。贫困县经历“首次确定、四次调整”，欠发达县是脱贫攻坚任务完成后政策体系的阶梯式延续，两者在划分标准、分类逻辑、政策焦点等方面有明显差异，但又相互关联。当前，欠发达县在乡村全面振兴推进过程中面临经济发展水平制约、人口接近中度老龄化、就业结构不合理、生态环境脆弱、产业发展落后、返贫风险仍在等问题，必须同步推进城镇化和乡村全面振兴，要切合当地实际，协调多方力量，着力增强内生动力，更好地探索发展的协调问题，处理好“一老一小”问题，更加长期注意防返贫工作。

Based on national county-level data, a three-dimensional identification framework has been constructed to precisely identify underdeveloped counties. The study finds that there are currently 528 underdeveloped counties in China, characterized by a spatial distribution pattern of “dense in the west and sparse in the east” and functional attributes of “multi-dimensional overlap.” Significant gaps exist between these counties and developed counties in terms of economic development and fiscal capacity. Poverty-stricken counties have undergone “initial designation and four adjustments,” while underdeveloped counties represent a phased continuation of the policy system after the completion of poverty alleviation campaign. While there are obvious differences between the two in delineation criteria, classification rationale and policy focus, they remain interconnected. Currently, in the process of advancing comprehensive rural revitalization, underdeveloped counties face challenges such as constraints on economic development levels, a population approaching moderate aging, an irrational employment structure, fragile ecological environments, backward industrial development, and persistent risks of reverting to poverty. To address these problems, it is imperative to advance urbanization and comprehensive rural revitalization simultaneously, tailor efforts to local conditions, coordinate multiple forces, focus on enhancing endogenous drivers, better explore development coordination issues, address the needs of the elderly and children, and maintain constant vigilance to return to poverty.

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国家社会科学基金重大项目（22&ZD059）；国家社会科学基金青年项目（24CGL090）；中国社会科学院大学研究生科研创新支持计划项目（2025-KY-054）