Abstract: A Galton whistle with a center bar is introduced and investigated. The numerical simulation method is used to study the changes of the pressure field and velocity field when the sound source works, the influence of the inlet pressure on the sound field distribution, and the effect of fluid medium on acoustic characteristics of sound source. The results show that the pressure field and flow field in the resonant cavity present periodic changes when the Galton whistle works stably. The sound source has strong sound directivity, and the sound field distribution under different intake the spatial distribution of pressures remains unchanged. The sound pressure level reaches a maximum value of 153 dB at the rear of the resonant cavity, decreases with increase of angle and reaches a minimum value at the front of the resonant cavity. As inlet pressure increases, the increases of sound pressure level in different directions are different. The increase at 0° is the maximum, then the sound pressure level decreases with increase of angle and reaches minimum at 180°. The acoustic characteristics (frequency and amplitude) vary with gas media. The sound source works at the highest frequency when low density steam is used as gas medium, and the variation of frequency and amplitude show an opposite trend, i.e., the higher the frequency, the smaller the amplitude.