The thought of Great Harmony is not only from Confucianism， but also related with Taoism and Mohism. Thought of “Great Harmony” and “well-off society” were mainly described in “book of Rites”. In mid time of Korea， Yulgok is proposed another social development goals—a slightly well-off society in addition to “Great Harmony” and “well-off society”. He expanded the extension theory and related theory of philosophy on the thought of “Great Harmony”. In Yulgok's view， a slightly well-off society is more practical and necessary before the king's dreaming of “ a well-off society ”. This thought stems from the historical environment in which Yulgok lived . But Yulgok's position is， the Great Harmony should be the ultimate goal whether it is“well-off society”or“a slightly well-off society”.