Driven by the concept of rural revitalization and sustainable development, vernacular architecture, as an important carrier of regional culture and ecological wisdom, is facing the severe challenge of modernization. Especially in severe cold zone, the traditional construction methods and thermal performance of vernacular buildings need to meet higher energy-saving and comfort requirements. This paper takes the vernacular architecture of Yalu River basin in China as the research object, focuses on the current situation and thermal performance of its envelope structure, and puts forward specific optimization design methods from the key structures such as walls, roofs, doors and windows. The research aims to improve the energy-saving performance of vernacular architecture, promote the deep integration of traditional construction wisdom and modern energy-saving technology, and provide theoretical support and practical reference for the green transformation and sustainable development of vernacular architecture.