Domain analysis is the activity of identifying and representing the relevantinformation in a domain, so that the information can be shared and reused in similar systems.But until now, no efficient approaches are available for capturing and representing the results ofdomain analysis and then for sharing and reusing the domain knowledge. This paper proposesan ontology-oriented approach for formalizing the domain models. The architecture for themultiple-layer structure of the domain knowledge base is also discussed. And finally, somegenetic algorithm-based methods have been given for supporting the knowledge sharing andreusing.