This study is an attempt to develop a knowledge base with Inference mechanism for document retrieval, which is the core element of expert system. The purpose of this study is to design the knowledge base in order to intellectually process user queries eventually improving the effectiveness of information retrieval, under the assumption that the user who wants to search a certain subject generally lack the prior knowledge about that subject. In this paper, some characteristics of Korean complex nouns are structurally analyzed and are represented in the knowledge base.