Retrieving reusable service components that satisfy the user?s requirements is a difficulty in component-based software development. This paper builds a domain ontology of computer, and proposes an approach to domain ontology-based software component retrieval. Different from the approach to keyword based retrieval, this approach can refine and extend the user?s initial query by query reasoning and provide fuzzy retrieval based on component similarity and relatedness. The whole approach extends the software reusable library to the World Wide Web. In the retrieval process, a user query in natural language is translated into RDF representation formats in order to augment retrieval recall and precision by deploying the same semantic representation technologies on both the user query side and the component side. We built the domain ontology using Protege2.1.