Abstract: Instead of a centralized information system, a peer-to-peer（P2P） full text information retrieval system is more scalable, cost effective and fault tolerant.It can cover the information at the edge of network and is more suitable for personalized resources services.However, P2P full text search is a very challenging problem, and the traditional broadcast ways are quite ineffective.Unstructured P2P information sharing systems （such as Gnutella, KaZaA） and structured P2P system can not support direct full text information retrieval.In this paper, a P2P full text information retrieval system is presented based on centroid method.A simulation program is created and the performance of the system is tested.Experimental results show that this is a steady system with high recall, good load balance and low resource usage.