Abstract: Mo+Y2O3 alloy powders were used to coat uniformly on the surface of 40Cr steel roller substrates by adhesive for the laser surface alloying treatment by a continuous wave CO2 laser in order to improve the organizational performance of the metal rollers. The effect of the rare earth oxide to the alloy layer on the hardness, wearing resistance, microstructure, and formation mechanism was studied with a scanning electron microscope, X-ray diffractometer, micro-hardness tester, and a wearing tester. Many good consequences were obtained after adding the rare earth oxide Y2O3. The crystal grains of the alloy layer were significantly refined. The boundary of crystal grains was strengthened. The uniformity and density of the microstructure were increased. The hardness and wearing resistance the alloy layer were considerably improved. The results show that it helps to improve the surface hardness and wear resistance of metal rollers