This study aims to establish the first county-level, population-based prospective cohort in Taining County, Fujian Province, China. The cohort will include at least 20,000 residents aged 18 years or older. The project will systematically collect questionnaires, physical measurements, laboratory tests, imaging data, and biological samples to build a multi-dimensional health database and biobank. Through 3-year follow-up, the study seeks to reveal the epidemiological patterns and risk factors of chronic diseases, characterize the natural course of multimorbidity and aging syndromes, and develop a comprehensive chronic disease management model suitable for rural and mountainous regions.