With the development of indexing and retrieval techniques and the trends of information retrieval environment becoming more and more user-friendly, existing guideline for international thesaurus establishment standards and basic term relations currently used in thesaurus have become to longer adequate. The purpose of this study is to present solutions to expanding term relations which will fit new information retrieval environment. This report views standards for ISO 2788 and ANSI/NISO Z 39.19, and compares and analyzes 20 thesaurus basis term relations currently used both at home and abroad(14 overseas and 6 in Korea) to find out problems and limitations. Based on findings of the study, this report suggests how to expand thesaurus basic term relations to accomodate changes in information retrieval environment.