Abstract: The catalyst for mild-hydrocracking of residual oil includes a porous alumina support a plurality of transition metals impregnated on the alumina support. The support has a specific surface area greater than 150 m2/g, a total pore volume ranging from about 0.25 ml/g to about 1.5 ml/g, about 20% of the pores having a diameter greater than 150 nm, about 70% of the pores having a diameter ranging from about 2 nm to about 150 nm, and about 10% of the pores having a diameter less than 2 nm. The plurality of transition metals include one Group VIII element and one or more Group VI elements.