On the basis of semantic information extraction with ontology, this paper proposes a framework of semantic information extraction system based on personal information domain and extends semantic extraction from the WEB area to the personal information domain. Building four ontologies including webpage, Emails, local database and file system, the system implements data communication in personal information domain with semantic association among their ontologies. Then the process of semantic information extraction system is described in detail. With an example of Email domain, relevant semantic information extraction algorithms are designed.