A Bronsted acid ionic liquid (IL), [C(4)mim]TFA (1-butyl-3-methyl-imidazolium trifluoroacetic acid), was synthesized and used as an extractant and catalyst for oxidation desulfurization (ODS) of thiophene from model oil with hydrogen peroxide as the oxidant. The major factors of the reaction were investigated in detail. The effect of different types of ILs on oxidative and extractive desulfurization capacities of model oil was tested, which proved TFA(-) > HSO4- > COO- > AlCl4- > AcO-. The reaction heat caused by H2O2 dissolved in IL was determined by a calorimeter.