Ancestral hall is a kind of common public buildings in the countryside, which is distinguished from other buildings in terms of its large volume, exquisite decoration and specific functions. Architectural decoration not only presents the building a specific appearance, but also greatly enhances its expressive power. Taking the decorative art of ancestral halls in Hunan Province as the research object, this article explores its form, connotation and cultural inheritance by using fieldwork and cross-disciplinary methods, so as to show its unique charm and cultural value. Rural ancestral halls and their decorations are important and precious cultural heritages in China's traditional cultures. Understanding, protecting and inheriting them is of great practical significance to the rural revitalization and inheritance of the Chinese cultural heritage.