As a revival paradigm for information sharing among distributed nodes in the network, P2P technology can pave the way for decentralized computing and enable more robust e-business applications. Peer-to-peer system is a continuously evolving system consisting of multiple heterogeneous information sources, and a huge number of users with diverse characteristics and needs. Currently, many research projects or practical applications have emerged which only support single keyword search, and few of them support semantic retrieval. In this paper, we propose a model of ontology-based semantic information retrieval systems according to hybrid ontology-based integration approaches, and describe the function of every module. In addition, we briefly discuss some key issues such as query and resource processing, resource searching, ontology mapping. Finally, we conduct a simulation experiment.