Abstract: Aiming at the problems of high grinding temperature, poor surface quality and low service life of grinding wheel in grinding process, this paper analyzed the mechanism of tangential ultrasonic assisted grinding from two aspects of kinematics and cutting force. Taking Ti6Al4V as workpiece material, the influences of ultrasonic amplitude, grinding depth, feed speed and spindle speed on material surface roughness were studied through comparative experiments. The experimental results show that, compared with the single grinding process, the surface roughness Ra is reduced by 25%～40% after the introduction of ultrasonic vibration, the surface pits are reduced significantly, and the surface topography changes significantly. With the increase of amplitude, the surface roughness of the material decreases by 40%. The roughness decreases with the increase of rotational speed by 25%. It is proved that the introduction of ultrasonic vibration can reduce the roughness and improve the surface quality of grinding workpiece. The results provide guidance for the selection of grinding parameters.