Abstract: PageRank，as the most important reputation ranking factor of Google，is prone to Sybil attack as recently research results prove.A higher ranking may offer an economic benefit.Based on some prevenient efforts on finding the best Sybil strategy to manipulate PageRank on its simplest version，the paper focuses on how to use strategy to optimize PageRank into its aimed ranking.Pay attention that the optimization work is done simulative without consideration for complex network environment，so it would still be far away to put such strategy into actual implementation，which is also the future work.

Key words: Sybil, PageRank, reputation system

摘要： 最近的研究证明Google的页面等级策略PageRank容易受到Sybil攻击。着眼于对如何构造Sybil攻击来优化PageRank值。提出了构造Sybile攻击的策略模型，考虑节点生成成本和迭代收敛性的前提下，证明了攻击的有效性。最后在模拟环境下对攻击进行了量化分析。

关键词: 女巫攻击, 页级, 信任系统