Optical coherence tomography (OCT) is a promising new imaging method for clinical diagnosis and scientific research. In order to obtain the morphologic structure and the scattering coefficient of in vivo human skin,an OCT system with 16 μm axial resolution and -90 dB detection sensitivity is created. With this system in vivo OCT image of human skin in several locations is formed. And the heterodyne signal expression is deduced from the OCT model based on the extended Huygens-Fresnel principle. Through the fit of heterodyne signal expression to the various parts of the OCT axial signal curve,the scattering coefficients is acquired. Structures of the stratum corneum (plamoplantar),the epidermis,and the upper dermis can be identified from the obtained cross-sectional images. The thickness of the stratum corneum and the epidermis are measured,as well as the scattering coefficients. It is demonstrated that OCT is a feasible method for investigation of morphologic structure of superficial layers of human skin.