Abstract: Liquefaction experiment of Shendong coal was run with 0.1t/d PSU. The residues were analyzed by means of microscopy. It is found that coal macerals change significantly. Liptinite and vitrinite convert entirely and inertinite converts partly. Unconverted inertinite can be observed from residues. There are also some newly formed components such as mesophase and semicoke. Mineral matters accumulate and keep their petrological features in coal. The reflectance of unconverted inertinite in residue dissolved by THF ranges from 2.0% to 3.0%,which is a little higher than that of high reflectance inertinite in coal. The high reflectance inertinite in coal is the main source of unconverted inertinite in residue.