Abstract: In order to analyze the acoustic signal of vertical downward air-jetting, the volume of fluid (VOF) model and Ffowcs Williams and Hawkings(FW-H) model are used to simulate the submerged gas air-jetting process. The accuracy of the selected model and the calculated results are verified by experiments. Based on the calculated flow field parameters, the generation mechanism and theoretical basis of acoustic signal are analyzed. The simulation results show that the flow field parameters have important effects on the acoustic signal. During vertical submerged downward air-jetting, the sound signal of bubble flow is significantly influenced by the considerable oscillation of bubble volume, which is caused by the bubble separation and air reinjection. At the same depth, sound pressure had the exponentially attenuates in the radial direction, and the acoustical signal around the circumference shows the characteristics of spherical source signal propagation.