關鍵詞自動擷取乃資訊檢索領域的基礎與核心技術。 本文中我們比較關鍵詞擷取 技術的幾種主要方法，說明每一種方法的優缺點、適用情況以及國內研究的提況。此外我們 也簡介自行發展的關鍵詞擷取方法運用於中、英文相關詞回饋的情況。初步的分析顯示其錯 誤率低（ 18 ％以下）、精確率高（ 50 ％以上）。其主要的缺點則是受限於查詢結果的多 寡，而查詢結果的多寡則與該查詢主題的館藏量有關。除了充實該類主題的館藏量外，亦可 透過索引典的自動建立與運用加以改進。

　　　　　Automatic keyword extraction is an important and fundamental technology in advanced information retrieval system. This article briefly compares several major keyword extraction methods, lists their advantages and disadvantages, and reports recent research progress in Taiwan area. Besides, this article also describes the application of a keyword extraction algorithm developed by the author in an information retrieval system for relevance feedback. The preliminary analysis shows that the error rate of extracting relevant keywords is as low as 18%, and the precision rate is over 50%. The main disadvantage of this approach is that the extraction results highly depend on the retrieval results, which in turn highly depends on the data hold by the database. Except collecting more data, this problem can be alleviated by the application of a thesaurus constructed by the same keyword extraction algoritm.