Abstract: Ionic liquid BImCl/CuCl was synthesized by two-step synthesis using 1-butylimidazole, HCl and CuCl as raw materials. Structure of BImCl/CuCl was characterized by FT-IR and FT-ICR MS. The interactions between BImCl/CuCl and thiol were analyzed by DSC, FT-IR and UV-vis spectra. The mechanism for the adsorption removal of thiol by BImCl/CuCl was discussed. It was found that the sulfur content in methyl tert-butyl ether (MTBE) could be reduced to lower than 5 μg/g via adsorptive distillation desulfurization process with BImCl/CuCl as adsorbent, and that significant deterioration in the desulfurization efficiency of adsorbent was not observed in a few recycling tests.