In information storage and retrieval system, controlled vocabularies are generally used to improve the recall ratio and to guide for indexers/users to select correct indexing/searching terms by regulating their forms as well as meanings. Thesaurs, a type of controlled vocabulary, nowdays accept ed by most of database producers. The objective of this study is to develope a method of Korean Language Thesaurus construction. This study covers 1) the definition of thesaurus, 2) a literatural survey on term relations and thesaurus construction method, 3) a suggestion for a practical construction method, 4) the display format of thesuari, and 5) tests and the results.