Abstract: In view of problems that existing knowledge expression methods are difficult to fully and effectively express innovative design knowledge of shearer, and knowledge expression of existing special knowledge base is not comprehensive enough and its retrieval efficiency is not high, in order to realize reuse of innovative design knowledge and experience of shearer, inspire ability of knowledge analogy transfer by designers, a multi-level and multi-granularity knowledge innovative design expression method of shearer was proposed. Six attributes are extracted including parameter, structure, function, principle, effect and domain. The attributes are described by knowledge with different abstract granularity, each granularity corresponds to abstraction levels of concept layer, semantic relationship layer and instance layer. Knowledge items are generated through feature attribute description, and multi-level and multi-granularity innovative design knowledge base of shearer is constructed. Through ontology reasoning and semantic extension, knowledge of different levels and different granularities is retrieved from local knowledge base and Internet resources, thus realizes multi-level and multi-granularity expression of innovative design knowledge of the shearer. The feasibility of the method was verified by improved structure design of shearer drum.