Abstract: The silicon was added in preparation to influence the performance of the hydrofinishing catalyst in lube hydroisomerization process. The results show that when SiO2 content is 30%, SA-30 the catalyst has a higher surface area and pore volume as well as stronger acid properties，and the best activity for aromatic saturation as well. Using the isodewaxed oil of hydrocracking tail oil as the raw oil and SA-30 as the catalyst，the best operation conditions for aromatic saturation are 230 ℃, 15 MPa, hydrogen/oil ratio of 500 and LHSV 1.1 h-1.

Key words: hydrocracking tail oil, hydrofinishing, lube base oil, aromatic saturation