Wear as a tribological process has a major influence on the reliability and life of journal bearings. The influences of Sn element doping on the microstructure and tribological properties of AlSn coatings on the surface of journalbearing alloy were investigated by magnetron sputtering. AlSn coatings exhibit equiaxed crystals. Phase compositions transform from crystalline to amorphous as grain sizes gradually decreases with increased Sn target current. Sn mainly exists as a simple substance composed of Sn-Sn bonds, reducing the friction coefficient of AlSn coatings sliding against a GCr15 steel ball. The hardness is 40IIV(0.025), and the lowest friction coefficient of AlSn coatings was 0.15 when I-Sn is 0.25A. Overall, the AlSn coatings have excellent microstructure and tribological properties.