Web search engines are very useful information service tools in the Internet.The current web search engines produce search results relating to the search terms and the actual information collected by them.Since the selections of the search results cannot affect the future ones, they may not cover most peoples interests.In this paper, feedback information produced by the users accessing lists will be represented by the rough set and can reconstruct the query string and influence the search results.And thus the search engines can provide self-adaptability.