This work proposes the approach to the modeling of the oil distillates catalytic hydroprocesses, based on consideration of the hydrocarbon chemical transformations, n-paraffin distribution in the feedstock by the number of carbon atoms in the molecule and n-paraffins reactivity in the target hydrocracking reaction, as well as the unsteady nature of the processes due to changes in the feedstock composition, technological modes and catalyst activity. Using the proposed approach, a mathematical model of the oil distillates hydrodewaxing process was developed. To consider the group composition in the model, an approach to recalculation of the feedstock fractional composition into the group composition was developed, as well as an approach to determination of n-paraffin distribution in oil distillates. Using the developed mathematical model, the study of the influence of hydrogen-containing gas consumption on the oil distillates hydrodewaxing process was carried out, and the process was optimized by such technological parameters as temperature and hydrogen-containing gas consumption. It was shown that when the process is carried out at optimal technological parameters, taking into account the composition of the feedstock and the dynamics of catalyst deactivation, the product yield is 1-6 % higher, and the catalyst resource increases by 10 % compared to the operation of the process at the actual (non optimal) technological parameters.