The work aims to explore the cultural connotation of bronze mirror patterns of the Han Dynasty and the redesign value of Chinese traditional patterns, and apply the patterns to modern product packaging design in an innovative way. Firstly, the social and artistic attributes of the bronze mirror patterns of the Han Dynasty were analyzed and the design method of extended semantic analysis was used to extract the intended vocabulary of patterns and construct an extension representation model to obtain the cultural semantic design interval of the bronze mirror patterns. Secondly, combined with the graphic thinking, the lexical semantics were converted into graphic semantics to carry out semantic expression analysis and quantitative value acquisition. Finally, the shape grammar was integrated with diagrams to obtain new patterns. Combined with bronze mirror unit pattern, a new pattern factor with recognition and design value was generated, and the design practice of new pattern factor was developed on product packaging. The extension theory can transform the tacit knowledge into the cultural primitive that can be expressed and evaluated rationally, and provide a feasible path for the inner and outer cultural connotation of the bronze mirror pattern of the Han Dynasty, and provide a continuity method for the representation of traditional Chinese pattern in the field of modern product packaging design.