Abstract: To overcome the challenges of low polishing efficiency and poor surface quality in silicon carbide polishing, researchers have employed an ultrasonic-assisted chemical mechanical polishing (CMP) process. This study focuses on investigating the impact of ultrasonic assistance on the flow field during the polishing process. The goal is to achieve smooth and damage-free polishing of silicon carbide surfaces. This study involves analyzing the properties of the polishing flow field under ultrasonic vibration. Fluid dynamics equations and energy conservation principles are utilized to understand these characteristics. Additionally, finite element analysis is employed to investigate the key factors that influence polishing efficiency in the flow field, including ultrasonic frequencies, amplitudes, and film thicknesses. The results show that ultrasonic vibration has a significant promoting effect on the polishing flow field, guiding the flow field to produce significant lateral shearing flow to enhance the overall polishing efficiency. The effects of ultrasonic action on the flow field vary with different film thicknesses. Analysis of simulation results indicates that as the film thickness decreases from 50μm to 30μm, the maximum velocity of the flow field increases from 84.28m/s to 105.68m/s, and the maximum pressure increases from 199.2MPa to 581.9MPa. It is evident that a smaller film thickness is more conducive to improving the polishing efficiency.