The impact of various process parameters on the surface roughness during the ultrasound turning finishing process was discussed. The best combination of process parameters was investigated, and the relationship between the various factors and the test indicators was analyzed by using the Taguchi methods. The test results indicate that the surface roughness is much smaller when the ultrasonic vibration is added during turning finishing. When no ultrasonic vibration was attached, the biggest factor of impact on the surface roughness is the speed, and the minimal of that is feed. When ultrasonic vibration was added, the greatest impact factor on the surface roughness is speed, and minimal of that is cutting depth.