Toluene insoluble (TI) is an important heavy components of coal tar. It significantly affects on residues upgrading and coke formation during slurry-phase hydrocracking. The structural and compositional evolution of TI were investigate in hydrocracking experiments with oil-soluble catalysts. Experiment results showed that the concentrations of TI after hydrocracked initially decreased and then increased as the increase of reaction temperature. And TI consisted organic aromatic compounds and inorganic species. At low temperatures, the TI evolution involved the thermal decomposition along with the elimination of heteroatoms groups. The Fe-1 S-x was formed by self-sulfurized from inorganic matters and was studied. At relatively high temperatures, the TI evolution included both mesophase and coke formation through the aromatic sheet stacking of rich-oxygen compounds. On the basis of experimental studies, the pathway of the TI evolution was proposed for slurry-phase hydrocracking. (C) 2017 Elsevier Ltd. All rights reserved.