Abstract: Replication techniques can bring many benefits such as  improving search performance, reliability and load-balancing in a P2P file-sharing system. This paper surveys  replication strategies that have appeared in the literature. The ideas behind each replication strategy and   the problem each one wants to address are listed. After analyzing the characteristics of those replication strategies, the direction of future work is suggested, which has some reference value for further study.

Key words: Peer to Peer（P2P） file sharing systems, replication scheme, search

摘要： 复制技术可以提高P2P文件共享系统的可靠性，改善查询性能和负载均衡。对文献中出现的各种复制策略进行总结综述，列出了各种复制策略背后的思想和拟解决的问题。在详细分析这些复制策略的特点基础上，对复制策略进一步的工作进行了展望并提出了建议。对进一步的研究复制策略有一定的参考价值。

关键词: 点对点文件共享系统, 复制策略, 查询