Abstract: The influence of preparation conditions on the properties of CoMoP hydrotreating catalyst was systematically studied by BET, TPR and UV-DRS techniques. It is found that preparation conditions have a distinctive effect on the properties of the catalysts and that lower temperature of impregnation, drying and calcination favors the reducibility of the active components. The air flows during drying and calcination influence the dispersion of the active phase. The amount of CoAl2O4 is related to the calcination temperature and decreases when the catalyst is calcined at a lower temperature. This study suggests that the catalysts with stable properties and a better utilization of the active species can be obtained by the precise control of the preparation conditions.