Abstract: Through the analysis of concepts of fear of cold and aversion to cold in medical books of past dynasties， it was found that with aversion to cold， referring to all cold symptoms initially， fear of cold partly meaned exogenous cold (Song Dynasty)and fear of cold and aversion became confused (Ming and Qing Dynasty). In the diagnostics of traditional Chinese medicine textbook of higher education， fear of cold and aversion to cold are kept carefully separated. Aversion to cold stands for exogenous cold， while fear of cold refers to endogenous cold with the differentiation of whether warming or close to heat can release coldness， which undoubtedly plays a certain role in clinical diagnosis. However， the author believes this may lead to negligence to the mechanism of cold symptoms， especially for new learners and result in misdiagnosis of some miscellaneous diseases. Therefore， the author put forward that the key to distinguishing fear of cold and aversion to cold is the defensive qi by judging whether it is weak or stagnant.