The hydrodesulfurization (HDS) of dibenzothiophene (DBT) were performed simultaneously over CoPtMo/LaY catalyst under high H$_{2}$ pressure. The structure and physical properties of this catalyst were characterized using XRD, IR and surface area analyzer. The origin of acid site was mainly Bronsted. The structures of impregnated molybdenum and platinum were deactivated by DBT to MoS$_{2}$ and PtS, respectively. The activities of the HDS and the hydrocracking increased with increasing temperature and pressure. They decreased with increasing the DBT mole ratio(DBT/n-heptane). They remained constant with increasing the H$_{2}$/H.C. mole ratio. With increasing pressure and DBT mole ratio, the products of secondary cracking increased. To perform simultaneous HDS and hydrocracking effectively, the optimum condition were 500.deg.C, 4MPa.