The application of ultrasound to casting processes can improve the quality of the casting through the effects of grain refinement, degassing, wetting, de-agglomeration and dispersion. For treating large volume of liquid metal, CFD study has recently developed an analysis tool capable to model acoustic streaming and cavitation in liquid metal. Especially, acoustic streaming is main factor for scale-up of ultrasound process because that is a non-linear physical effect which can assist in effective dispersion of cavitation bubble with propagation of the ultrasonic wave in liquid. Therefor in this study, the CFD modeling was developed to study the effect of ultrasonic frequency and amplitude on acoustic streaming. The resonant frequency was controlled as 15, 20, and 25 kHz and the amplitude varied as 28, 38, 48, 66 Ám. We measured the acoustic streaming velocity in the fluid and modeling was performed to predict the effective range in liquid.