The ionic liquids used herein were alkyl-containing ammonium-aluminum chloride ionic liquids system, which were made by the reaction of short-chain alkyl ammonium salts and aluminum chloride. The factors influencing stability of gasoline and the importance of improving it were described in this article, so was the characteristic of ionic liquids. A novel way to improve the stability of gasoline using ionic liquids was studied herein, as well as the study of decreasing the basic nitrogen content and the sulfur content of mercaptan, treating the gasoline and decreasing the olefin content of gasoline with supported ionic liquids catalyst on a small scale. After treating, the sulfur content of gasoline decreased to 0 nearly, and the basic nitrogen content decreased greatly too, whereas the octane number (RON) of gasoline increased a little. To improve the catalysis of ionic liquids and prolong the using life of ionic liquids, a buffering agent was added into ionic liquids. Ionic liquids catalyst, as ...