A process for preparation of catalyst to produce ultra-low sulfur diesel (ULSD) from high refractory sulfur feedstock. The catalyst composition comprises a modified alumina carrier, impregnated by metal of group VIB is in the range of 15-25% and metal of group VIIIB is in the range of 1-5% as oxides. The catalyst prepared in the present invention produces highly dispersed MoS2 active sites on the modified carrier. The catalyst produces ultra low sulfur diesel (ULSD) along with improved cetane, density reduction and endpoint reduction.