Abstract: In order to inhibit the serious corrosivity of conventional ionic liquids (ILs), a series of ILs containing benzotriazolium cations were synthesized. The physicochemical properties, thermal stabilities of these synthesized benzotriazolium ILs and the corrosion to steel were studied. The tribological properties of the synthesized ILs as lubricants for a Steel-Steel System were evaluated on an SRV friction and wear tester at room temperature and 150 ℃. The worn surfaces were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. It is found that,the benzotriazolium ILs possessed lower thermal stability but better friction-reducing and anti-wear ability than conventional imidazolium IL, which had the same anion as the benzotriazolium one. And more importantly, these benzotriazolium ILs had no corrosivity to steel, which was one of the important reasons for their better anti-wear ability.