Conceptual design is the early phase in product design process. It is critical to product life-cycle. The core of conceptual design is the solving process and utility of knowledge to realize the process. The goal of product design is the attempt to realize product function. The formulation of function definition makes it necessary to apply knowledge to implement the solving process for conceptual design. On the basis of analyzing current research and applications of conceptual design process theory, the function-based conceptual design process in which Ontology is applied is provided in this dissertation. The application of ontology knowledge to the conceptual design process is also discussed. The followings are the main contents in this dissertation:1. Based on researching the theories and realizing methods of conceptual design process, the role played by function in conceptual design process is mainly discussed. After analyzing existing problems in function definition, this dissertation proposes a function representation method through using function semantic; uses ontology theory to capture domain knowledge in conceptual design process. On the basis of research mentioned above, the conceptual design solving process model FSFM is established, and characteristics of the model and the way of realizing is discussed.2. In order to support computer-aided conceptual design, the information conceptual representation is proposed in meta-model FPS of FSFM. General information elements are given and data model is provided for FPS. To encapsulate the information, CPML Schema is set up though extension markup language. This research lays the foundation of solving process knowledge sharing, reusing and collaborative design.3. This dissertation analyzes the basic theory and idea of Ontology, and proposes function ontology, principle ontology and structure ontology as the knowledge representation in conceptual design solving process. On the base of function semantic natural language, this dissertation mainly discusses the method that the function ontology base is automatically constructed through semantic similarity. Conceptual dependency theory is applied to build function ontology semantic tree and to realize the relationship of function semantic. The knowledge representation of function ontology, principle ontology and structure ontology are discussed respectively with ontology modeling primitive.4. Key technique is analyzed in knowledge reusing and sharing of conceptual design; an object-oriented knowledge base system is built; case-reasoning to describe knowledge reusing of conceptual design is presented in the conceptual design process; WEB-based collaborative design of FSFM model is analyzed to provide unified syntax operation for data and semantic of collaborative design process.5. A conceptual design solving process is established to support computer-aided conceptual design. Manipulator is taken as an example to illuminate the partial realization of conceptual design.