Objectives : In this study, the changes of concept of Bianzheng(辨證)[syndrome differentiation] in the traditional medical history are investigated for the purpose of understanding conditions of Korean Medicine in modern times. Methods : The concepts of Zheng(證)[syndrome] and Bianzheng[syndrome differentiation] in Sanghanron(傷寒論) and many important medical literatures were selected and analyzed to overview the historical changes of those. Results : To the modern ages, the concept of Zheng had included the two kinds of concepts, that is, symptom/sing and syndrome with slight changes of meaning. As a abstract meaning of syndrome, Zheng(證) has been systematized and complicated with the times, that means changes of syndrome differentiation. The concept of Zheng has been recognized as the symbol that expresses the characteristics of Traditional Medicine since the modern age that concepts of sign and symptom have flowed from Western Medicine into Traditional Medicine. Conclusions : One of the main key of studies about Bianzheng(辨證) in future would have been harmonizing the balance between the two trends of modern Traditional Medicine, ideation and objectification.