In this article, a liquid chromatographic separation scheme was developed to separate hydro-treated lube base oil into six different fractions according to their polarity, i.e., saturates, light aromatics, middle aromatics, heavy aromatics, nitrogen-containing compounds, and oxygen-containing compounds. Each individual fraction and subfraction acquired was analyzed by a series of instrument technology such as refractive index method, infrared spectroscopy, ultraviolet spectrum (UV), and X-ray photoelectron spectra in detail. These analytic data not only demonstrated the effectiveness of separation into narrow compound classes but also characterized their chemical group composition in detail. This research result indicated that a suit of methods to separation and characterization of group composition aimed at hydro-treated lube base oil was relatively and successfully developed, at the same time. X-ray photoelectron spectra shows great potential for characterization of polar subfractions.