[Purposes] The Sub-cellar house in the Yuanshui River basin exhibit significant issues in terms of suitability for the elderly. Hence, this study aims to modify Sub-cellar house for elderly-friendly renovation, which can not only improve the living environment of the elderly but also promote the modern adaptability of traditional dwellings. [Methods] Through on-site investigations and questionnaire interviews, the research team gathered insights into the renovation needs for age-friendly living among the elderly. The study identified common issues regarding the age-friendliness of sub cellar house interiors and developed strategies for their renovation. These strategies encompass aspects such as spatial integration, modern construction techniques, and the application of age-friendly components. [Findings] To solve the key problems faced by Sub-cellar house such as missing flat functions, outdated facilities for elderly people, poor physical and lighting conditions, corresponding renovation suggestions were proposed, combined with barrier-free use parameters and the modern adaptive living needs of elderly people. The renovation schemes including re-planning the indoor space of Sub-cellar house, adding elderly-adaptive facilities, and introducing modern construction technology injected new vitality into traditional vernacular houses. [Conclusions] This study can supplement and enhance the construction theory of elderly-adaptive vernacular housing in the Yuanshui River, help local authorities cope with the growth of the elderly population, and provide a certain reference for the elderly-adaptive design of traditional buildings in other regions.