The purpose of this study is to investigate and analyse the revised contents of the history class in the Korean Decimal Classification(KDC), 5th edition, and then identify problems and propose the revised contents for the KDC, 6the edition. Major analysed areas are divided into four. First, geographic area table is discussed. It includes extension of the geographic area table, emphasis of hierarchical structure in the geographical area, revision of North Korean geographical names, extension of subgeographical structure of major nations in the world, and revision of nations in the central and west Asia. Second, Korean time period is extended. Third, the notes of entries of the Chinese and Japanese history areas are shorten. Fourth, the geographical and personal names are changed their native pronunciation, specially Chinese and Japanese. For the revision of the KDC, 6th edition, four areas are discussed: first, Korean geographic areas would be categorized by broaden area, second, the areas are arranged from the capital of the nation to others, third, foreign geographical names would be used their native names, and last, time period would be categorized by years.