As unstructured information becomes richer and more complex, alternative information organization methods are needed to more effectively and efficiently retrieve information from various systems, including the Web. The semantic supporting of unstructured information management system is in favor of distributed resources integration and manipulation. Unstructured information organization and information retrieval are proposed when applying Ontology to it in this paper. A framework of Ontology-based information management is presented. The development of the domain ontologies DB is shown by concrete process and steps. Based on the ontologies DB, the annotation of unstructured information is obtained. Information retrieval which consists of concept-matched retrieval and rule-based reasoning retrieval is proposed with the help of information annotation. The experiment results show that rule-based retrieval has better recall and shorter retrieval time than fact-based retrieval and relationship-based retrieval