CdMoO_2S_2 H_2O was synthesized in laboratory. Its thermal stability was investigated bymeans of Th ermog ravimetric analysis (TGA), and its tribological characteristics at temperatures upto 500℃ were examined by sliding a Sialon ceramic and GCr15(AIS152100) steel ball against aW18Cr4V(AISI T1) steel disc on a high temperature ball-on-disc tribometer. The morphologies ofand the elemental distributions in the worn surfaces of the ceramic and GCr15 ball were observedand determined by scanning electron microscopy (SEM) equipped with energy dispersion spec-trometry (EDS). The chemical states of some typical elements in the worn surfaces of the ceramicball and steel ball were explored with X-ray photoelectron spectroscopy (XPS). As the results,CdMoO_2S_2 showed good lubricity for Sialon ceramic/W18Cr4V steel and GCr15/W18Cr4Vpairfrom room temperature to 400℃. The XPS analytical results indicate that CdMoO_2S_2 experiencedtribochemical reactions during the friction process at 300℃, thereby generating S and Mo of highervalence for both pair. While for GCr15/W18Cr4V pair, produced MoS_2. SEM observations of theworn surfaces of the Sialon ceramic and GCr15 ball show that a surface protective film composedof the lubricants and their decomposed products was formed thereon, which contributes to keepthe sliding surfaces off contact and abate the adhesion and scuffing on the lubricated surfaces,therefore to decrease the friction coefficients. Its thermal stability was investigated by means of Th ermog ravimetric analysis (TGA), and its tribological characteristics at temperatures up to 500 ° C were examined by sliding a Sialon ceramic and GCr15 (AIS152100) steel ball against aW18Cr4V (AISI T1 The morphologies of and the elemental distributions in the worn surfaces of the ceramic and GCr15 balls were observed and determined by scanning electron microscopy (SEM) equipped with energy dispersion spec-trometry (EDS) . The chemical states of some typical elements in the worn surfaces of the ceramicball and steel ball were explored with X-ray photoelectron spectroscopy (XPS). As the results, CdMoO_2S_2 showed good lubricity for Sialon ceramic / W18Cr4V steel and GCr15 / W18Cr4Vpairfrom room temperature to 400 ° C. The XPS analytical results indicate that CdMoO_2S_2 experiencedtribochemical reactions during the friction process at 300 ° C, the while observations were made on the surfaces of the Sialon ceramic and GCr15 ball show that a surface protective film composed of the lubricants and their decomposed products was formed thereon, reby generating S and Mo of higher volatility for both pair. While for GCr15 / W18Cr4V pair, produced MoS_2. which contributes to keepthe sliding surfaces off contact and abate the adhesion and scuffing on the lubricated surfaces, therefore to decrease the friction coefficients.