Abstract: Because of lacking for uniform international standard and network topology model，the P2P network presents a confusion environment all along.This paper start form“The Small World Model” and the users’ interesting，gives a new P2P topology model IGP2P，which based on interest grouping.By the idea of grouping，each group will be grouped by a central node.For the purpose of reducing the harm for the network by single point failure，a new strategy SCNS is put forward.And bring cache into IGP2P，not only enhance searching speed rate and successful rate，but also it does good job to the network’s stability.

摘要： P2P网络由于缺乏统一的国际标准和固定的网络拓扑模型，一直都呈现出一片混乱的局面。以“小世界模型”和用户兴趣为出发点，提出了一种基于兴趣分组的P2P网络拓扑模型—IGP2P。采用分组的思想，由中心节点统一管理每个组。为了减少单点失效带来的危害，提出了备用中心节点策略SCNS，并在搜索算法中引入了缓冲池（Cache），不仅提高了搜索的效率和成功率，而且对减少P2P网络带宽占有量和提高网络的稳定性都有很大的帮助。