It is widely recognized that the chipless finishing process — the burnishing process can be used efficaciously to reduce the surface roughness of components. But most of previous works published concentrated on the conventional burnishing process and experimental researches in the last few years. There are some limitations on the conventional burnishing process in reducing surface roughness. Ultrasonic elliptical vibration burnishing (UEVB) process is proposed. Theoretical model is established to analyze theoretical surface roughness. Steel 45 was selected as material for making the specimens in the experiments and a new device developed by us was used for the burnishing process. The comparison shows that the surface roughness in describing the burnishing process is better than the conventional burnishing process obviously.