The invention belongs to the technical field of catalysts, and particularly relates to a denitration catalyst with a sulfur oxidation preventive characteristic and a preparation method thereof. The catalyst comprises, by mass, 1% of V2O, 5-10% of WO3, 1-2% of BaO and the balance being TiO2. The preparation method of the denitration catalyst includes three steps of preparation of impregnation liquid, loading of active components and roasting. As the denitration catalyst is modified by BaO, the modified denitration catalyst has good pore structure, obvious change of the acid center position is avoided, oxidation of SO2 on the surface of the catalyst is suppressed, and NO removal rate is higher than 95%. The denitration catalyst with the sulfur oxidation preventive characteristic and the preparation method thereof are adaptable to the characteristic of high sulfur content of domestic coals, the service life of the catalyst is prolonged effectively, and flue gas denitration cost is lowered.