Abstract: Addressing the core imperative of inheriting historical context and drawing upon the spatial gene research paradigm, this paper establishes a three-stage formulation framework for urban design in county central areas: ‘identification-decoding, evaluation-screening, and translation-design'. By dissecting three-dimensional cultural context genes-material space, cultural society, and institutional governance-and employing the Analytic Hierarchy Process (AHP) to filter core characteristic factors, this study systematically translates these genetic factors into overall spatial forms, landscape style systems, and planning implementation guidelines. Grounded in an empirical study of Guiyang County, Chenzhou City, Hunan Province, this research addresses the prominent dilemmas of ‘urban homogeneity' and ‘form without spirit' in traditional county-level urban design. Ultimately, it enhances the localization and operability of planning, providing a scientific approach and a replicable paradigm for the distinctive development and sustainable growth of county-level cities.