Abstract: The hydrodesulfurization and hydrodenitrogenation kinetics of the 4th side stream of vacuum tower of Maoming Co. Sinopec were studied in a trickle bed hydrogenation unit using FF-46，a NiMo/Al2O3 hydrofining catalyst, at conditions of total pressure of 6~15 MPa，temperature of 608.15~638.15 K，liquid hourly space velocity of 0.75~2.00 h-1 and gas to liquid volume ratio of 600. A hydrodesulfurization and hydrodenitrogenation kinetic model of the 4th side stream was established. The experimental data were fitted by the Levenberg-Marquardt and the general global optimization method, and then the model was verified by the real data. The results indicate that the reaction orders of HDS and HDN are 1.4 and 1.7, respectively, and the activation energies are 74.60 kJ/mol and 72.90 kJ/mol, respectively. The established model can well predict the sulfur and nitrogen content in the product.