The sweat gland and peripheral vessels underneath skin surface are a typical minute organ governed by the skin sympathetic nerve, and have important physiology functions to control of body temperature or nutrition support and maintenance of a peripheral organization. Dynamics of the mental sweating of sweat glands and the peripheral vessels reflect the activity of a sympathetic nerve. In this paper, I demonstrated the dynamic analysis of the mental sweating of the eccrine sweat glands and the dynamics of the small artery of human finger by optical coherence tomography (OCT).