Abstract: P2P search system distributes resource index on nodes in order to implement resource matching and computation of the final search result.The type of index has great influence on the way and performance of computing search result.The current P2P search models based on DHT adopt the index type that is named in this paper as superset index.This type of index inevitably has defects in performance.Thus，this paper proposes the concept of exact index and builds a P2P search model on the basis of exact index.The proposed model realizes good load balance and returns the search result in short time.

Key words: Peer to Peer（P2P）, search, exact index, load balance

摘要： P2P搜索系统需要在节点上分散存放资源的索引，以实现资源的匹配和搜索结果的计算。索引的类型对于如何计算搜索结果和与之相关的性能有很大的影响。目前基于DHT的P2P搜索模型使用的是称之为超集索引的索引类型。该类型的索引不可避免地具有种种性能问题。为此，提出精确索引的概念，以及构建于精确索引之上的P2P搜索模型。该模型达到了相当好的负载平衡性能，并能快速返回搜索结果。

关键词: P2P, 搜索, 精确索引, 负载平衡