Abstract: Clinicians are enthusiastically involved in etiologic research since they are paying more attention to the effect of etiology in management of disease in recent decades. However, there is a lack of understanding of the etiological view and etiologic research methods of clinical medical field. This article briefly introduces the etiologic concept, classification and research framework in epidemiology, in order to help clinicians to form a more integrated top-level design before the etiologic research.