The history of medicine has a strong correlation to the ancient development of epidemics. Although the study of the history of East Asian Traditional Medicine does not put much emphasis in understanding the flow of medical history in relation to epidemics, it largely impacted the development of this epidemic and the compilation and evolution of treatment methods. The same was true for Korea as they linked development of epidemics, unusual natural conditions, and social phenomenons from ancient documents. This study methodically classifies the epidemics mentioned in ${ulcorner}$三國史記${lrcorner}$ and concludes on how ancient Koreans understood epidemics.