A novel ionic liquid ［BMIm］SbF ₆ was synthesized effectively by microwave radiation and characterized with FT-IR. The results show that the ionic liquid is one of typical ionic liquids based N, N'-dialkylimidazolium. The molecular structure and resonance frequency of the ionic liquid was calculated with density function theory (DFT) of quantum chemistry. The calculated data of IR resonance frequency are consistent with the experimental data. The molecular structure of the conjugant of ［BMIm］SbF ₆ and thiophene was also simulated and calculated. The data indicates that the stability energy of the conjugant is increased compared with the summation of stability energy of ［BMIm］SbF ₆ and thiophene. This implied that there is a better extractive speciality between ［BMIm］SbF ₆ and thiophene. The property of the extractive desulfurization of ［BMIm］SbF ₆ was tested in certain conditions with simulative gasoline. The result indicates that there was the better property of desulfurization for this ionic liquid. The ratio of once desulfurization could be reached 15%.