Abstract: In the small-scale test apparatus, the deep hydrodesulfurization property of FHUDS-2 catalyst was evaluated by using Zhenhai mixed fuel. Additionally, the transformation mechanism of sulfides on the FHUDS-2 catalyst was studied. The results showed that 4, 6-DMDBTs were the most difficult removal sulfide, and it has low sensitivity to temperature. The ratio of 4, 6-DMDBTs increased gradually in product. FHUDS-2 catalyst has excellent performance of deep or ultra-deep hydrodesulfurization. Under the conditions of partial pressure of hydrogen 6.4 MPa, volume space velocity 1.5 h^-1, volume ratio of hydrogen to oil 500, and reaction temperature 360~370 ℃ or reaction temperature 360 ℃, partial pressure of hydrogen 6.4 MPa, volume ratio of hydrogen to oil 500, and volume space velocity 1.0~1.5 h^-1, FHUDS-2 catalyst could produce the deep and ultra-deep diesel fuel satisfying the European Ⅳ and European Ⅴ emission standards.