Abstract: The laser cladding of Ni25 is carried out by synchronous ultrasonic vibration and non-ultrasonic vibration. The difference of appearance, microstructure and hardness of the cladding layer under two modes is analyzed. It is concluded that synchronous ultrasonic vibration can significantly improve cladding. The appearance of the layer increases the height of the cladding layer, the depth of the molten pool and the width of the cladding layer. The cavitation effect of the ultrasonic vibration refines the microstructure of the cladding layer and increases the grain boundary, thereby increasing the appearance of the cladding layer micro hardness.