MoS2 (labeled as MoS2⁃1 and MoS2⁃2) was prepared by in⁃situ decomposition of water⁃soluble molybdenum⁃based catalyst and oil⁃soluble molybdenum⁃based catalyst.In order to explore the effect of two types of molybdenum catalyst in slurry⁃bed hydrocracking and preliminary theoretical analysis,the catalysts were characterized by XRD analysis,particle size analysis,SEM analysis and evaluation of reaction performance.Autoclave evaluation results showed that,compared with adding oil⁃soluble catalysts,the transformation rate and coke yield rate were better than that by adding water⁃soluble catalyst.The results of XRD analysis showed that the crystalline state of MoS2⁃1 was poor.The characteristic peaks of MoS2⁃2 were sharp and the crystalline state was good,so the hydrogen could be activated to activate hydrogen and the coke yield rate was reduced.The results of SEM analysis and particle size analysis showed that the MoS2⁃2 was smaller and the diameter was mainly 1~5 μm.MoS2⁃1 was larger and the diameter was mainly 6~10 μm.MoS2⁃2 catalyst had smaller particle size and uniform particle size distribution which could provide more hydrogenation active centers to improve the conversion rate of the reaction.