Abstract: The 3rd and 4th vacuum cuts of Saudi Arabia Middle crude oil were separated into four components: paraffins, light aromatics-saturates, middle aromatics and heavy aromatics by the solvent separation techniques (dewaxing and/or solvent extraction). The main properties, hydrocarbon types and structural parameters of VGOs and their components were characterized by GC, GC-MS and NMR, and the separation efficiency of the solvent separation methods was studied. The results show that 24.4%~36.8% of alkanes in VGOs come into the paraffins obtained by solvent dewaxing, about 12 times that of cycloalkanes, the alkane content in the paraffins is 88.3%~95.2% and the carbon number of the paraffins is normally distributed. The aromatic contents in heavy aromatics and middle aromatics components obtained by solvent extraction were 85.4%~88.8% and 73.2%~78.5%, respectively. As the components become heavier, the CN, CP, RA, RN and atoms of S and N in average molecular formula increase, but CA decreases. The separation percentage of aromatics with three and more rings was 72.8%~75.5%, about 5~8 times that of alkanes and 4~5 times that of cycloalkanes. So the selectivity and efficiency are high for separating alkanes and aromatics by solvent separation.