Abstract: TC4 titanium alloy is a typical difficult to machine material. To resolve the impact of poor thermal conductivity on milling performance, an ultrasonic vibration assisted milling process is proposed to improve the milling quality of titanium alloy materials. The simulation model of PCD milling cutter and TC4 titanium alloy workpiece was established using finite element software Abaqus, and the influence of ultrasonic vibration on cutting edge temperature of PCD milling cutters was analyzed; A single factor method was used to design ultrasonic vibration milling tests, and the effects of different ultrasonic amplitudes and tool rake angles on cutting edge temperature, milling force, and surface roughness of PCD milling cutters were studied; Compare the test and simulation results to verify the reliability of the simulation model. The results show that ultrasonic assisted milling can significantly reduce the cutting-edge temperature and milling force, and effectively improve the machining quality of the workpiece surface. Compared with ordinary milling, the average cutting-edge temperature of ultrasonic milling has decreased from 421.5 ℃ to 241.9 ℃, with a decrease of 42.6%. The milling force decreased from 104.65 N to 87.05 N, with a decrease of 16.8%. The average surface roughness is 0.316 μm dropped to 0.228 μm, decrease is 27.8%. The effect of ultrasonic amplitude on surface roughness is more significant than that of milling cutter rake angle, and the simulation and test results are basically consistent, with an average error of 4.6%.