This study aims to define the relationship between brain and heart through several literatures about oriental medicine and the conclusions are as follows. Heart in oriental medicine is called as Sinmyeongjishim(神明之心) which has a close connection with Mind, Consciousness, Emotion, and Physiological instinct of Drain in modern medicine. According to Oriental medicine, Brain stores Wonsin(元神) as Heart stores mind(神). Heart is where mind rests whereas Brain is where mind reveals. The external evidences that prove the relationship of Heart and Mind are as follows: First, with ears, eyes, mouth, and nose the subject of cognition is recognized as Sinmyeongjishim(神明之心). Second, Bulin(不仁), which means decreased movement power and sensibility of limbs, proves that Sinmyeongjishim(神明之心) is involved with movement power and sensibility of limbs. The physiological evidences that prove the relationship of Heart and Mind are as follows; First, Heart as the operation of Sinmyeongjishim(神明之心) manages language. Second, Heart is related with Tongue. Third, Heart is linked to Ears through the ear hole. Fourth, Heart is a store of Mind. Fifth, the five viscera control emotional and psychological activities. The pathological evidence of the relationship of Heart and Mind is that the symptoms of heart disease which are related to Sinmyeongjishim(神明之心) are also related to the functions of Brain. Though Brain has a close connection with Heart in oriental medicine, it is recognized that there are distinctive symptoms of disease of Brain and Hyeolyookjishim(血肉之心) respectively. The relationship of Heart and Brain has been researched in this study, even though there are not enough written materials about oriental medicine. But the fact that the majority of Heart operation is deeply connected with Brain activities cannot be denied. Therefore the research of Heart should be done as well as Brain in the clinical study of Brain.