Abstract: A new lubricating material,WS₂ submicron particle, was used as an additive of high temperature grease and its effects on tribological performance of grease at elevated temperatures were investigated. The morphologies, surface distribution and depth profiles of typical elements on the worn surfaces of steel balls were analyzed by Electron probe microanalysis (EPMA) and Auger electron spectroscopy (AES). Results showed that at elevated temperatures WS₂ submicron particle improved the tribological performances of grease, especially at high temperature. During sliding, adsorbed WS₂ film and tribo-chemical film composed of elements Fe and S on the worn surfaces effectively reduced friction and wear and thereby improved the anti-wear, anti-friction and extreme pressure properties of grease.