This paper aims to explore the design application forms and principles of traditional leaky window elements in modern furniture. The research on the leaky window elements was conducted from such perspectives as subject type, functional form, modeling feature and cultural connotation symbol. Extension semiotics theory was used to analyze the application path of leaky window elements in modern furniture design, and design innovation was conducted from the cultural symbolism, reconstruction of pattern elements and the unity of furniture design themes. Based on the favorable feasibility and pertinence of the extension semiotics theory for the innovative design method with leaky window elements in modern furniture, it can provide an effective reference for the innovative method of modern furniture design, and it is of great significance for expanding the innovation path of modern furniture design and developing Chinese traditional culture.