MgO nanosheets were employed to prepare CoMo catalysts with different Co/Mo ratios (CoMo/NA-MgO) by an aqueous co-impregnation method. CoMo/NA-MgO displayed an increase in the catalytic activity for hydrodesulfurization of dibenzothiophene as the Co/Mo ratio increased in the CoMo catalysts, and it reached maximal activity at the Co/Mo ratio of 0.5. The reaction rate constant (k) and turnover frequency of CoMo/NA-MgO-0.5 (2.7 x 10(-7) mol g(-1) s(-1) and 7.9 x 10(-4) s(-1), respectively) were higher than those of conventional CoMo/gamma Al2O3 (2.1 x 10(-7) mol g(-1) s(-1) and 4.1 x 10(-5) s(-1)). Characterization results revealed that more basic sites on NAMgO strengthen the interaction between MoOx and NA-MgO, leading to CoMo/NA-MgO with better MoOx dispersion than that of CoMo/gamma-Al2O3. In addition, an increase in Co/Mo for CoMo/NA-MgO weakened the interaction of MoOx with NA-MgO, leading to more MoOx species transformed into a less stacked type II CoMoS phase after sulfidation, improving direct desulfurization activity.