Ellipsometry is a method to measure refractive index: n, extinction coefficient: k, and thickness of surface layers of materials by measuring changes of polarization of reflected light at the surfaces. Generally, n and k change with the wavelength of light. The way of the change is dependent on the microscopic structures of the materials. Therefore, by continuous change of wavelength of the prove, light spectroscopic ellipsometry provides much more information on the materials than the ellipsometry with a fixed wavelength. If the results are combined with the analysis of optical models of material structures, it can fulfill its functions to more extent. The recent rapid development of abilities of small size computers, together with the development of optical elements and systems, has allowed these analyses to be much more time-saving and hence realistic. Recent information about typical spectroscopic ellipsometry is outlined and referred to its instrumentation and the data analyses procedures.