Molybdenum nitride (gamma-Mo2N) and Co-promoted molybdenum nitrides (Co-Mo-N) catalysts with high surface area have been prepared from the reaction of MoO3 and Co-Mo oxides with N-2-H-2 and characterized by XRD and BET. The results of measurement of hydrodesulfurization(HDS) of dibenzothiophene(DBT) supported the following conclusions: (1) gamma-Mo2N and Co-Mo-N have higher HDS activity and selectivity for C-S bond breakage in dibenzothiophene; (2) different pretreatment conditions affect the HDS activity and selectivity; (3) the HDS activity of the gamma-Mo2N is significantly improved with the addition of a Co promoter.