In this study, a molecular-level kinetic model of fluid catalytic cracking (FCC) slurry oil (SLO) hydrotreating in a trickle-bed reactor was developed. The physical and chemical properties of SLO were measured, and the data were used as input to tune the composition model parameters. A series of reaction rules were collected and established in terms of the reaction family according to the hydrotreating reaction mechanism. After applying the reaction rules on all the SLO molecules, a reaction network was generated containing 5,753 molecules and 15,830 reactions. The kinetic model was then built employing the Langmuir-Hinshelwood-Hougen-Watson (LHHW) formalism. The kinetic model parameters were reduced using the linear free energy relationship (LFER) and quantitative structure-reactivity correlations (QSRCs). The kinetic model was delivered to the trickle-bed reactor model, and the model parameters were tuned using experimental data obtained from a pilot hydrotreating unit. The obtained SLO hydrotreating model showed good agreement between the predicted and experimental product properties and composition under various processing conditions. The model was able to predict the concentration distribution of each species along the reactor. In addition, the influence of reaction temperature on the aromatic content and thiophene compound content was also evaluated. (C) 2018 Elsevier Ltd. All rights reserved.