Abstract: Ultrasonic assisted grinding test and common grinding test were carried out on TC4 titanium alloy at room temperature. The effects of grinding speed, feed depth and ultrasonic vibration on the grinding force for the alloy were studied and compared. The surface machining quality of samples was analyzed. The results show that the normal grinding force and tangential grinding force for the ultrasonic grinding decreased with increasing grinding speed and the decreasing amplitude decreased, and increased with increasing feed depth and the increasing amplitude increased. The normal grinding force and tangential grinding force for the ultrasonic grinding sample were much lower than those for the common grinding sample. There were less debris adhering to the surface of ultrasonic grinding sample, and the surface machining quality was better.