The present work aims to synthesize the CoCrNi/W/Agx composites with the high wear-resistance under ambient air and vacuum conditions. The friction and wear properties of the CoCrNi/W/Agx composites and CoCrNi medium entropy alloy were fully evaluated, and the chemical components and microstructural evolution of the tribo-films were observed and analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy. The self-lubricating mechanism of the CoCrNi/W/Agx composites under ambient air and vacuum conditions was investigated. Increasing the Ag content increased the thickness of the tribo-films improving the friction and wear properties of the alloys, and the thickness of the tribo-films formed on the worn surface of the CoCrNi/W/Ag1.0 composite was about 150 nm. The CoCrNi/W/Ag1.0 composite exhibited an evident improvement in tribological performance, with a high wear-resistance of 2.79 x 10-5 mm3/N center dot m under vacuum condition and a volumetric wear rate as low as 1.35 x 10-5 mm3/N center dot m under ambient air condition.