Abstract: Distribution for ultrasonic pressure field in a vessel was simulated, and the results are in good agreement with experimental results. On this basis, the flow field was simulated by the use of the distribution of the ultrasound field. Results were compared with experimental results obtained by particle image velocimetry. The influence of acoustical and geometric parameters for the flow field was discussed. Results have indicated that ultrasonic power enhances the flow field, and the maximum of the liquid velocity is linear to the ultrasonic power in a range. Within ultrasonic frequency range from 100 kHz to 472 kHz, the flow field was enhanced by the increase of frequency. The liquid velocity is proportional to the square of the frequency when flow is laminar flow. The liquid velocity is proportional to the square root of the frequency. The influence of the vessel size on the flow field was also discussed: with increasing distance from the transducer to the walls of the vessel, the flow field velocity decreases.