World-wide changes in clean fuel regulations have accelerated the research works for reducing sulfur in fluidized catalytic cracking (FCC) gasoline. In this work, NiSO4 and Ni(AC)(2) were supported on nano-HZSM-5 Al2O3, and SiO2 supports by impregnation to prepare catalysts modified by NiSO4 and NiO. The catalysts were characterized using X-ray powder diffraction (XRD), nitrogen adsorption (BET), NH3 temperature-programmed desorption (TPD), Fourier transform infrared (FTIR) analysis with adsorbed pyridine, H, temperature-programmed reduction (TPR), and differential thermogravimetric (DTG) analysis. NH3-TPD shows that the acid sites and acid strength is increased after NiSO4 modification and decreased after Ni(AC)(2) modification. FTIR results indicate that most of the increased acidity is Lewis acid. Infrared spectra before and after pyridine adsorption demonstrate that there is a strong interaction between S=O in SO42- and alumina oxides. The interaction makes NiSO4 on the surf-ace of alumina oxides harder to decompose than pure NiSO4 and SO3 in sulfate anion much more difficult to be reduced. This interaction results in more stable desulfurization activity of NiSO4/Al2O3 than that of NiO/Al2O3. However, there is no interaction between NiSO4 and SiO2.