Optical coherence tomography (OCT) is a novel technique with high resolution for rapid, noninvasive imaging in living biological tissues (human body). With this technique, a thin "optical section" within a thick biological specimen can be obtained. This technique not only has higher axial resolution but also has higher longitudinal resolution than ordinary optical microscopy. In this paper a low-coherence optical tomography system including a fiber-optical Michelson interferometer and a confocal scanning microscope is described, and theoretical analysis is given to this high-precision microscopic imaging system based on optics, mechanics, electronics and computer. Meanwhile, various kinds of potential applications of OCT system in clinical medicine are described in details, such as in ophthalmology, dermatology, cerebrum, dentistry and internal medicine, etc. The characteristics of OCT technology and limitations of OCT application are also investigated, and some schemes are studied to make OCT technology more practical. The future of OCT technology in medical application is predicted. The research of this paper can provide a new, effective technique method of high-speed, high-resolution and noninvasive detection for clinical medicine, and this is very important in deepen and widen the field of OCT study.