This paper presents a fundamental investigation of the surface generating mechanisms involved in Tangential ultrasonic vibration assisted grinding (TUAG) for Titanium alloys processing. The relationship between ultrasonic vibration, grinding parameters and surface quality is illuminated; the grain paths chasing phenomena is pointed out to describe the surface forming, the surface topography and micro structure are studied and analyzed by a series of experiments. The influence of grain paths overlap and interfere on surface roughness and grinding force are studied respectively. A series of experiments designed by three-variable four-level fractional factorial is used to evaluate the machining performance. The experimental results are employed to clarify the surface features of Titanium alloys fabricated by ultrasonic vibration assisted grinding, in order to explain the interaction effects of the ultrasonic parameters on material removal rate, grinding force and surface quality. Experimental results show that the grinding force of TUAG is less than that of CG. At the spindle speed of 2000rpm, the grinding force in TUAG is 13N less than that in CG, which greatly optimizes the machining process and improves the surface machining quality.