As the concern about health is increased, the importance of preventive medicine that prevent disease in advance to overcome boundary of disease remedy gets emphasized in the whole world. The fundamental thoughts of oriental medicine are the harmony between the human body and nature, the unified idea regarding mind in the same light with body, and the symmetry of the cosmo dual forces. And oriental medicine is a kind of study that has developed on the ground of prevention thought. from old days, it has been developed the preventive medicine at is called 'Yangseng(養生; recuperation)' etc. with the clinical medicine. The preventive medicine of oriental medicine was taking a serious of the first preventive medicine of an incurable disease thought and the prevention thought that belongs to the second and third preventive medicine is described through the whole oriental medicine. Also the clinical and preventive medicine to apply to the clinics have an in- separable relation. Therefore I inspected the part of the preventive medicine described in some oriental medicine books and studied the characteristics of preventive medicine of oriental medicine as follows; First, the preventive medicine of oriental medicine has the characteristics that is emphasized generally in the first preventive medicine and wholly it is composed in the system of the first, second and third preventive medicine. It has the presentative theory such as 'Jungkijonae sabulkaghan(正氣存內 邪不可干; If good energy is in body, a disease. dosen't occur)', 'Husajukpung Phijeyushi(虛邪賊風 避之有時; When e infectious disease like plague break out, they must avoid the place occurring the disease)', 'Chuninsangeung(天人相應; The harmony of nature and human)' etc.. This is intimately related to the incurable disease thought of the inside diameter and oriental medicine has pursued that. Second, due to the most prerequisite theory of disease production, the balanced condition of environment, the cause of a disease and host is called the health. As oriental medicine has the system of aetiology like that, we can see the host and environments are importance most of all. Namely we can think of the relation of host >> environment > the cause a disease Up to date Jungkijonae Sabulkaghan(正氣存內 邪不可干) that the most oriental medicine doctors have had a knowledge is not whole theory but a pan of oriental medicine science and it is included in oriental medicine theory to avoid infectious disease such as Husajukpung Phijeyushi(虛邪賊風 避之有時). Third, according to the natural result of the first and second contents, we can know that its characteristics stress the remedy without drugs. Because Jungkijonae Sabulkaghan(正氣存內 邪不可干), Husasukpung Phijeyushi(虛邪賊風 避之有時), and Chuninsangeung(天人相應) mean that they prevent disease in condition of freedom from ailment, We can prevent the disease production through the positive preventive methods such as exercise, spirit, food and innate prevention etc.. fourth, the preventive medicine of oriental medicine has developed with therapeutics and it contains all oriental medical methods such as host, environment, exercise, acupuncture and moxibustion, innate or postnatal methods. Also it is the general preventive medicine that has fundamental philosophy of oriental medicine; for examples, the unified idea, the harmony of nature and human, and the unity of mind and body. fifth, to develope the above scientific merit and special features, the preventive medicine of Oriental medicine must be objectified and reemergent stud? gets more and more essential from now on. Especially we need to have the scientific concern of Oriental medicine about the cause of a disease, environmental hygiene, industrial sanitation, and personal hygiene etc..