7075-T6 aluminum alloy specimens were tested for machining experiments by using ordinary cutting (CT) and the vibration cutting (UVC) processing methods, to analyze the influence of cutting parameters on the work piece surface roughness. Experimental results show that: In the same amount of feed and depth of cut, speed with the turning changed, the surface roughness of ordinary cutting reduced first decreases and then increases again, but with the speed increased into the high-speed, the surface roughness become stable; The surface roughness uptrend with the feed rate increased of ultrasonic vibrations hard turning and ordinary hard cutting; In the same cutting speed and feed rate, with cutting depth increased ,7075 Aluminum ordinary hard cutting surface roughness increased, but the ultrasonic vibration cutting surface roughness first decrease and then increase. Through the analysis of experimental data obtained and the observations of the microscopic morphology of the machined surface after turning, the advantage of ultrasonic vibration machining in difficult materials processing is confirmed.