Abstract: Semantic knowledge of a product such as product usage, functional characteristics and design principles is essential during its conceptual design stage to guide the design process.However, content-based 3D model retrieval focuses on products'geometric similarity rather than their functional similarity.To solve this problem, a function-based 3D model retrieval method is proposed.First, a functional semantic ontology of 3D models is built, by which the 3D model retrieval based on functional semantics can be carried out.The functional semantic ontology is then used as an instruction to guide the standardized labeling of the function of the 3D model.Moreover, in case one function may be not a comprehensive description of the target model, a retrieval algorithm supporting multiple function retrieval at the same time is also proposed, which is used to calculate function semantic similarities between models and then sorts them.Finally, an example is taken to illustrate that the search result can satisfy the requirements of conceptual design and contribute to design reuse and innovative design.