The existing chemical mechanical polishing process is hard to meet the requirement of quality of fiber array components. Based on the inverse piezoelectric effect of piezoelectric ceramics and ultrasonic vibration principle, a kind of modeconversion ultrasonic elliptical vibration device with sandwich transducer is presented for improving the quality of fiber array component surface polishing. A ultrasonic vibration system for chemical mechanical polishing was designed, and the FEM analysis and test for the designed system have been carried out. The results showed that the error of resonance frequency between test results and design results is less than 5%. The bidirectional amplitude of the ultrasonic elliptical vibration are 4 μm and 2 μm respectively.