The Co-based alloy coatings are prepared on the GCr15 bearing steel surfaces by the ultrasonic vibration assisted laser cladding technique. The microstructure and the high-temperature oxidation behaviors are analyzed in detail under the condition of 750 ℃/100 h. The results show that the ultrasonic vibration does not change the phase compositions of cladding layers and only more uniform and fine equiaxed structures are formed in the near surface layers. After high-temperature oxidation for 100 h, the coating follows the parabolic oxidation rule. Compared with those of traditional laser cladded coatings, the oxidation films on the surfaces of coatings by ultrasonic vibration assisted laser cladding are finer and denser, and there are no obvious oxidative cracks and spalling defects. Meanwhile a large number of high-temperature CoCr2O4 spinel phases with good stability are generated. The oxidation weight gain and oxidation index are reduced by 19.2% and 50.8%, respectively. The high-temperature oxidation resistance is enhanced.