AbstractBased on the theory of acoustic resonance spectroscopy (ARS), the measurement system of ARS was established for detection of gas content in a gas‐liquid mixture. The resonant amplitude (RA) and resonant frequency (RF) were studied with various gas flow rate in a cylindrical resonance cavity. The experimental results showed that both the RF and the RA decreased exponentially with the increase of gas flow passing through the cavity, and the attenuation rate of the RA was faster than that of the RF, although both of them were affected by the gas flow rate. Furthermore, the analytical expression for the RF was derived in a cylindrical cavity with a homogeneous flow model, and the relation curve of the RF with gas flow rate was numerically calculated. The results showed that the RF decreased with the increase of gas holdup. The attenuation rate of the RF was fast when the gas holdup was small. This conclusion had been verified by our measurement results. The theoretical and experimental results showed that the ARS method (ARSM) could be used in gas detection in a gas‐liquid medium, which paved a way for gas rate detection in a gas‐liquid flow in a production well.