The technologies of slurry-phase hydrocracking of heavy oil and the latest development of dispersed catalysts were reviewed. Catalysts for slurry-phase hydrocracking of heavy oil have undergone two development phases, that is, heterogeneous solid powder catalysts and homogeneous dispersed catalysts. The homogeneous dispersed catalysts are divided into water-soluble dispersed catalysts and oil-soluble dispersed catalysts. Solid powder catalysts have low catalytic activity, which will produce a large number of solid particles in bottom oil; thus it is difficult to dispose and utilize. Dispersed catalysts are highly dispersed and have greater surface area to volume ratio. Therefore, they show high catalytic activity and good performance. They are desirable catalysts for slurry-phase hydrocracking of heavy oil.