The load-carrying capacity, wear and friction properties of three S-(1H-benzotriazol-1-yl)methyl alkyl xanthates added to a synthetic lubricant (diester) were evaluated using a four-ball test machine and an optimal SRV tester. Their thermal stabilities in static air were examined by TGA analysis. The results when compared with those of zinc butyloctyl-dithiophasphate (ZDDP) show that the three novel compounds possess an excellent load-carrying capacity and antiwear property similar to ZDDP. the rubbed surfaces were investigated using X-ray electron spectroscopy (XPS) and the antiwear mechanism, was discussed.