Toluene insolubles (TI) in coal tar is harmful to the downstream hydrotreating, and it may be difficult to be removed by conventional filtration. The TI is separated from coal tar which is washed by toluene and centrifugated at 2000 rpm and analyzed by Fourier transform infrared (FTIR) spectra, scanning electron microscopy (SEM), particle size measurements, X-ray Diffraction analyses (XRD) and elemental analysis. It is concluded that TI in coal tar is present typically as globular aggregates. The primary particles range in size from less than 0.5μm to about 20μm. Characterization of TI in the coal tar showed that it is a nitrogen and oxygen rich material. TI is mainly inorganic elements representative of quartz, albite and calcite associated with kerogen material.