在資訊檢索中，「相關理論」是重要的基礎概念；而在資訊檢索的技術發展中，「模糊理論」亦是重要的議題。本文除針對此二種理論進行深入介紹與概念內涵比較解析外，並以文獻計量方法驗證二者的應用核心領域，及進行二者的關聯研究。文末嘗試依據上述結果，推測「相關」及「模糊」在「資訊檢索」領域中可能的應用發展趨勢。

The “Relevant Theory” and the “Fuzzy Theory” are two important topics in Information Retrieval (IR). In addition to thoroughly explicating the two theories, this paper adopts the method of bibliometrics to verify and analyze the respective core fields of applications and the connection between the two notions of “relevant＂ and “fuzzy.＂ Furthermore, this study also suggests probable extensive applications of the two theories in the future trends of information retrieval.