中文摘要：

关键字竞价排名服务已引起越来越多学者的关注和研究，但已有研究成果均未考虑保留价格对关键字竞价双方的影响。在Winner—pay和All—pay两种支付规则下的保留价格关键字竞价模型基础上，分析保留价格对两种支付规则下搜索引擎提供商期望收益的影响，结果表明：保留价格的放大效应会导致Winner-pay支付规则下，搜索引擎提供商的期望收益不小于All—pay支付规则下，搜索引擎提供商的期望收益。

英文摘要：

Ad Words auction is studied quantitatively. This article, based on Ad Words auction model with reserve price proposed in the Winner-pay and All-pay auction, analyzed how reserve price is influential to the bidding strategies and search engine providers＇ expected revenue in the two auctions. And it is shown that because of the amplification effect of reserve price, the expected revenues in the two auctions may not be equivalent.