Abstract: Aiming at meeting the demands of diesel quality upgrading, a new generation of FHUDS-5 catalyst for ultra deep HDS was developed by Fushun Research Institute of Petroleum and Petrochemicals based on modified alumina carrier developed newly, optimizing the combination of active metals and improving metal impregnation technology. The results of pilot plant tests showed that compared with FH-UDS, FHUDS-3 and other catalysts, FHUDS-5 catalyst possessed high relative HDS and HDN activities, to achieve the same HDS result its reactive temperature was lower more than 10 ℃. Meanwhile, FHUDS-5 catalyst demonstrated good stability and feed adaptability. The commercial application results on low pressure diesel hydrotreating units indicated that FHUDS-5 catalyst exhibited excellent HDS activity, clean diesel fuels meeting the emission standards of National Ⅲ, Ⅳ and Euro V could be produced with said catalyst.