To meet the needs of consumers to combine traditional cultural connotations with food packaging, a research method for extracting traditional pattern features under extensible semantics is proposed. By analyzing and screening the patterns of Tang Dynasty gold and silver artifacts, the target pattern elements were established, and an extensible semantic model was constructed; Perform semantic lexical extension analysis on pattern primitives to obtain the maximum design value range. Visualize and analyze feature semantics using graphical thinking, and derive and evolve them using shape grammar. Taking a certain mooncake packaging design as an example, several design schemes were designed using this method, and fuzzy comprehensive evaluation was conducted on them, achieving high satisfaction. The feasibility and effectiveness of the design method based on extensible semantics have been verified, providing new ideas for the inheritance and development of traditional patterns in modern food packaging design.