A maximum oil yield in the NEDOL coal liquefaction process was obtained with coal containing 76-78% carbon, while gas and water yields decreased with an increase in the carbon content. On the other hand, residue yield increased with an increase in the carbon content and this was attributed to an increase in asphaltene [(hexane insoluble)-(toluene soluble)] in the residue. From the experimental results, it was inferred that decomposition of the asphaltene is inevitable for improvement of the oil yield and that prolonged residence time in the liquefaction reactors is the most effective and practical measure for decomposing the asphaltene under the operating conditions of the NEDOL process. The average structure of the hexane soluble, asphaltene and preasphaltene [(toluene insoluble)-(THF soluble)] in the liquefaction residue exhibited the similar structural parameters in coals tested in the NEDOL coal liquefaction plants. The asphaltene fraction was then extracted from the residue by commercially applicable extraction conditions following which the extract was hydrotreated. About 35% of the extract was recovered as oil, which is lighter than 811K boiling point, by hydrotreatment. Furthermore, coal liquefaction experiments that used the extract as a part of solvent were conducted and an increase in total liquefaction oil yield was confirmed comparing with a coal liquefaction experiment without the extract.