In this paper, we propose a trust-oriented evaluation method for information retrieval methods based on computing the content coverage of the search results. At first, for a user given query, we collect the related resources available on the Internet. We then sketch out an overview (called topic-sketch) of these resources. We compute the content coverage of the search results to evaluate the retrieval methods to see whether they comprehensively find and provide us information, by comparing the resource overviews and each result. In other words, the content coverage is also useful for estimating the content comprehensibility provided by a Web page on a certain topic. Therefore, we can also use the content coverage as a measure to re-rank the search results. Some preliminary experimental results are shown in this paper to validate our method.