The decentralized structure together with the self-organization and fault-tolerant features makes P2P network an effective model for information sharing, however, the content location remains a serious challenge of large scale P2P networks. In this paper, the SemreX is introduced, which is a P2P system for literature retrieval. Semantic-similarity-based P2P overlay and routing algorithms are proposed for SemreX. Experimental results show that searching in semantic overlay greatly improves the efficiency of search.