Abstract: The catalyst used for the slurry phase hydrocracking of VGO (Vacuum Gas Oil) from Kelamayi, Xinjiang, was separated from the products and analyzed by using XRD and XPS. The crystal structures of the catalysts were identified as NiS（Ni7S6）, MoS2 and Fe1-xS. The catalytic performance of molybdenum, nickel and iron was studied respectively for the slurry phase hydrocracking using diphenylmethane as the model compound and VGO from Kelamayi as the reactant. The results showed that, during the slurry phase of heavy oil hydrocracking, the catalyst of metal sulfide reacted on the chemical reactions. The free-radical intermediate H· formed on the surface of the catalyst could react with the free-radical of big molecular and restrained the formation of coke during the reaction.