Abstract: Due to the excellent low-frequency characteristics of the liquid cavity vibration of the overflow ring transducer, a calibration method using the sound field inside the liquid cavity of the overflow ring transducer is proposed in this paper. Firstly, the characteristics of the liquid cavity of the overflow ring transducer in rigid cavity are analyzed. Based on existing rigid tank, a calibration system without excitation platform is constructed by using the lowfrequency comparison method, in which, the overflow ring transducer is taken as the low-frequency sound source and the overflow ring liquid cavity is taken as the vibrating liquid column with openings at both ends. Through measurements, it is determined that the center position of the liquid column with a height of 15 cm is the best measurement point for the comparison method, and the change of radial sound pressure at this point is no more than 5% at 100-1 400 Hz. A spherical hydrophone of Ф20 mm is calibrated by the comparison method. Within 100-1 000 Hz, the maximum deviation between the measurement result and the standard calibration result is 0.8 dB, and the measurement uncertainty is 1 dB. The results show that the low frequency calibration system based on the overflow ring liquid cavity is feasible.