Abstract: In this work, dodecyl benzenesulfonic acid and triethanolamine were applied to synthesize a kind of halogen-free sulfonic alcohol amine ionic liquid (S-IL) as water lubricating additive, and a commercial ionic liquid (tetra ricinolein acid ester, L4) was chosen as reference. Nuclear Magnetic Resonance showed that as-synthesized S-IL additive had a definite molecular structure and high purity. Subsequently, solubility in water was considered for S-IL compared to L4, the result revealed that the former was superior to the later. The reason was that the ionic configuration of S-IL can electrolyze out cations and anions in water, and the cationic triethanolamine species can produce hydrogen bonds with water molecules to promote the dissolution. In contrast, L4 was a neutral molecule with the longer alkane chains that generated the hydrophobicity. The anti-corrosive durability of additives was the most concerned issue in water lubricating system. The electrochemical corrosive tests were used to inspect the corrosion resistances of S-IL, L4 and pure water, with the assistance of iron plates and copper plates serving as the working electrode, respectively. Noted that no matter iron electrode or copper one, S-IL enabled the more excellent corrosion resistance than other two references, which implied that S-IL can efficiently form the protective film on the metal interface. Tribological tests were performed to evaluate the lubricating performances of S-IL as additive compared to L4 and pure water in ball-on-disk configurations on steel-steel friction pairs. Although both S-IL and L4 presented the similar sliding status and approximate friction coefficient, relative to that of pure water, S-IL additive can suffer the much higher load pressure up to 900 N than extreme pressure load of L4. The load patience was further verified on four balls tester on such extreme load, with the smooth and steady friction coefficient observed across the running time. Next, the different metal plates (Cu, Al, Ti and Mg) sliding against steel ball were employed to explore the available extents. All of testing results displayed that S-IL was the optimal candidate in the friction reduction. S-IL additive had high compatibility and tolerance to these different friction pairs and can provide efficient and stable anti friction ability. The SEM images of worn surfaces lubricated with S-IL, L4 and pure water exhibited that S-IL gave the smoother and shallower scars without corrosion spots. XPS was conducted to delve the lubricating mechanism of S-IL based on the variation of elements and valence state of worn surface from different metal plates. The difference of action mechanism of IL on the interface of different metal friction pairs was analyzed in detail. The results manifested that the physically adsorbed film as the major and chemically reacted one as the minor contribute synergistically to the prominent friction reduction and anti-wear for steel-steel and steel-aluminum mates. However, the reverse contribution was observed for steel-copper and steel-titanium mates. The rest of magnesium mate showed that the completely chemically reacted film was predominant to the interfacial tribo-film. In all, compared with the commercial water-based additives, S-IL had excellent friction-reducing functions and extreme pressure properties, which were mainly attributed to the physical/chemical adsorption of polar group (-SOO-) in the molecular structure of ILs on the surface of metal friction pairs, and the tribo-chemical reaction film contributed by reactions between active elements S and N with metal substrate. This work provided a guidance for the lubricating application of ionic liquid additives in practical mechanical accessories.