Hydrodesulfurization is significant petrochemical process, especially in last decades in view of the fact that legislative requirements are incessantly increasing. Presence of sulphur in fuel is undesirable with respect to ecology due to exhaust with SO2 production and also sulphur containing compounds are cause of poisoning of car catalyst. Sulfur removal is performed by catalytic hydrotreatment process, when besides hydrodesulfurization (HDS), which is primary process, is under way organic nitrogen removal during hydrodenitrogenation (HDN) and oxygen (hydrodeoxygenation HDO). Aromatic compound decrease during hydrodearomatization (HDA) is also take place. From this point of view hydrodesulfurization catalysts can be taken for one of the most important catalytic materials used in industry processes. Its activity significantly influenced product quality and economics of whole process. Raw material for engine fuel production is highly complex mixture containing various hydrocarbons and sulphur heterocyclic compounds. Its character has an important influence on hydrodesulfurization effectiveness. In hydrotreatment input streams are usually present thiophenes, benzothiophenes, dibenzothiophenes and they alkylated derivates. Reactivity of these compounds is different, given to different molecular structure. The most problematic can be considered dibenzothiophenes alkylated in position 4 and 6. In this case is sulphur atom steric hided by presence substituents and its removal from molecule is problematic. This work deal with evaluating of reaction condition influence, especially reaction temperature and initial concentration of selected sulphur compounds, on hydrodesulfurization kinetic. Experimental data were evaluated by first order reaction kinetic, its results was used as input estimation for hydrodesulfurization process mathematical model definition, which is able to cover evaporation of reaction components to gas stream.