This study is interested in one of the hydrodynamic mechanisms induced by High Intensity Focused Ultrasound (HIFU) propagation in a liquid medium, the acoustic streaming phenomenon. The latter is a flow generation caused by acoustic energy viscous dissipation during acoustic wave propagation in a fluid medium. Particle Image Velocimetry (PIV) technique was used to determine velocity fields in an infinite aquatic medium subjected to a focused ultrasonic field. These tests were carried out with a parametric variation, namely, of the applied acoustic pressure at the focus (ranging from 2 to 18.4 bars) and of the transducer frequency (550 kHz and 1 MHz). The experimental results allowed to characterize the mean streaming flow and in particular to evaluate the maximum axial velocity magnitude reached in the focal zone and conclude how the velocity increases with ultrasound wave amplitude and frequency.